Succubi and Incubi: Sexual Demons, Offspring Generation, and the Tradition of Saint Thomas Aquinas

A Comparative Study Across Christian Demonology, Ancient Mythologies, and World Religions

Introduction

The belief in spiritual entities capable of engaging in sexual relations with human beings spans virtually the entire history of humanity. From Mesopotamia to medieval Christianity—by way of Egypt, Greece, Rome, India, China, Japan, Islam, and Indigenous traditions—narratives describe spirits, demons, gods, or supernatural beings visiting men and women during sleep. These encounters were said to trigger erotic dreams, illness, pregnancy, the birth of heroes, extraordinary bloodlines, or the slow draining of vital energy.

Among all these traditions, few exercised as profound an influence on Western thought as the writings of Saint Thomas Aquinas (1225–1274). In his Summa Theologiae—specifically in the Prima Pars, Question 51, Article 3 (Utrum daemones possint generare?)—Aquinas directly addresses the issue of incubi and succubi. His conclusion became one of the most influential formulations in medieval demonology: demons possess no natural body and therefore cannot generate life on their own; however, they can act by using human biological matter obtained through extraordinary means.

This interpretation, later expanded by 15th- and 16th-century inquisitors and demonologists, fueled hundreds of inquisitorial trials, theological treatises, and popular beliefs.

But to what extent was this idea exclusively Christian?
Was it merely a medieval adaptation of far older beliefs?

This investigation seeks to answer these questions through a comparative analysis across dozens of religious traditions, ancient texts, philosophical works, medieval treatises, historical research, and contemporary scientific studies.

PART II — SAINT THOMAS AQUINAS AND THE DOCTRINE OF SUCCUBI AND INCUBI

Chapter I: Saint Thomas Aquinas and the Construction of Medieval Demonology

Saint Thomas Aquinas (1225–1274) is regarded as the preeminent philosopher and theologian of Scholasticism. His goal was never to write a standalone book on demons, but rather to construct a comprehensive philosophical system that harmonized Aristotelian philosophy with Christian doctrine.

The topic of incubi and succubi appears within the Summa Theologiae, specifically in the Prima Pars, Question 51, Article 3 (Utrum daemones possint generare? — "Whether demons can beget offspring").

To understand his thought, one must remember that Aquinas operates from four fundamental premises:

God created only good angels.
Certain angels rebelled and became demons.
Demons remain purely spiritual intelligences.
Spirits do not possess reproductive organs.

This last point is decisive. Contrary to popular medieval belief, Aquinas asserts that demons have no inherent biological capacity for reproduction. This marks a significant divergence between Scholastic theology and popular folklore.

Chapter II: Question 51 of the Summa Theologiae

In the article dedicated to incubi and succubi, Aquinas poses an exceptionally specific question:

"Can demons father children?"

He initially presents arguments in favor, drawing directly from popular medieval accounts. Many individuals at the time claimed:

Women had been impregnated by demons.
Men had been attacked in their sleep.
Children were considered "offspring of the Devil."
Monks had been tempted by female entities.

Aquinas even cites a tradition well known since Saint Augustine:

"It is a common opinion, confirmed by many testimonies, that certain demons, called incubi, frequently solicit and lie with women."

Immediately following this, however, he begins to dismantle a literal, biological interpretation. According to his framework:

"No spirit can produce semen."

This statement is foundational. It eliminates the hypothesis of genuine demonic reproduction.

Chapter III: How Aquinas Explains Demonically Attributed Pregnancy

Here we find one of the most famous passages in all of medieval demonology. According to Aquinas:

A demon could first act as a succubus, assuming a female appearance.
In this form, it would collect human semen from a man.
Later, it would assume a male form, becoming an incubus.
It would then introduce that same semen into a woman.

As Aquinas writes:

"The same demon that acts as a succubus to a man can become an incubus to a woman."

Note the critical detail: according to Aquinas, there is no creation of life by the demon. There is only transport. He continues:

"The generation belongs to the human semen, not to the demon."

Therefore, the resulting child would be biologically human, never half-demon. This conclusion stands in stark contrast to countless popular legends that spoke of literal demonic hybrids.

Chapter IV: The Philosophical Mechanics According to Aquinas

Aquinas's theory relies entirely on Aristotelian physics. Angels are immaterial intelligences without metabolism or reproduction. Consequently:

They lack DNA, blood, cells, and physical organs.
They cannot produce gametes—neither eggs nor sperm.

According to Aquinas, the demon merely moves pre-existing matter, acting as an invisible intermediary. This explanation preserves two core theological principles:

Only God creates life.
Only human beings generate human beings.

By framing it this way, Aquinas avoids attributing a divine-like creative power to demonic entities.

Chapter V: The Influence of This Doctrine Across Europe

Despite Aquinas’s philosophical caution, his ideas were ultimately reinterpreted in a far more radical light by 15th- and 16th-century demonologists. Later authors cited his authority to justify a wide array of popular beliefs, including:

Demonic pregnancies
Sexual pacts with the Devil
The birth of witches
Changelings
Nightly visitations

These concepts later saturated works such as the Malleus Maleficarum (1487), Compendium Maleficarum, Démonomanie des Sorciers, as well as French, Spanish, and German inquisitorial literature on witchcraft.

However, many of these texts extrapolated significantly beyond what Aquinas had actually written. Where he argued that demons cannot generate life, later authors increasingly suggested near-literal demonic lineages.

Comparative Analysis

When comparing Aquinas's stance with other religious traditions, key differences emerge:

Mesopotamia: The Lilû and Ardat-Lili spirits were believed to engage in direct sexual relations with humans.
Jewish Tradition: Lilith evolved into a figure associated with nocturnal seduction.
Ancient Greece: Lamia and Empusa fulfilled similar functional roles.
Islam: Narratives involve certain jinn that can seduce or torment humans in dreams, though interpretations vary widely across schools of thought.

In many of these non-Scholastic traditions, the narrative remains strictly mythological rather than philosophical. Thomas Aquinas, by contrast, seeks to rationalize these beliefs through Aristotelian metaphysics, explicitly denying that spirits can biologically create life.

Probabilities in Light of Modern Science

From the standpoint of modern science, the primary hypotheses explaining these historical accounts include:

Sleep Paralysis: Episodes where a person partially awakens during REM sleep, experiencing a sensed presence, chest pressure, and occasionally tactile or sexual hallucinations. This well-documented medical phenomenon accounts for many accounts traditionally attributed to incubi and succubi.
Lucid and Erotic Dreams: Vivid experiences that, depending on cultural context, may be interpreted as encounters with supernatural entities.
Hypnagogic and Hypnopompic Hallucinations: Visual, auditory, or tactile perceptions occurring during sleep-wake transitions.
Psychological and Cultural Factors: Religious beliefs, sexual repression, guilt, and cultural expectations heavily shape the interpretation of these subjective experiences.

Regarding the hypothesis that an incorporeal entity could transport human genetic material between individuals to cause pregnancy, there is no reproducible empirical evidence to support it. Modern biology explains fertilization strictly through the fusion of gametes under established physiological conditions; experimental data does not confirm spiritual intervention in this process.

Thus, while Aquinas’s texts remain historically pivotal for understanding medieval demonology and Scholastic philosophy, modern science views his explanations as products of 13th-century cosmology rather than verified biological or physical phenomena.

PART III — HISTORICAL INVESTIGATION REPORT

Chapter VI: The Sources Used by Saint Thomas Aquinas

To properly grasp Aquinas's theory of succubi and incubi, one must ask: Where did he acquire these ideas?

Contrary to common belief, Aquinas did not invent this doctrine. He synthesized, organized, and reinterpreted far older traditions, reconciling them with Aristotelian philosophy and Christian theology. His primary influences include:

The Bible (particularly Genesis and Job)
The writings of Saint Augustine
The works of Saint Gregory the Great
Saint Augustine’s De Civitate Dei (The City of God)
Aristotle
Pseudo-Dionysius the Areopagite
Widely circulated medieval folklore

One of the most critical figures for Aquinas was Saint Augustine (354–430). In Book XV of The City of God, Augustine notes:

"There is a very general rumor, supported by the testimony of many who have had experience or who have heard from those who have, that Indwellers [incubi] have often presented themselves to women and succeeded in accomplishing sexual intercourse with them."

Augustine presents this not as dogmatic proof, but as an acknowledgment of contemporary tradition. Aquinas uses this as a springboard for philosophical inquiry—asking not whether the stories existed, but how they could be explained without violating the principles of divine creation.

Another key influence was Isidore of Seville (c. 560–636), whose Etymologiae collected various beliefs about spirits, demons, and supernatural beings. Additionally, Aquinas relied on Aristotle's Metaphysics and On the Generation of Animals, which shaped his views on reproduction, form, matter, and causality.

Chapter VII: The Medieval Interpretation of Dreams, Visions, and Nighttime Experiences

In the Middle Ages, the boundary between the physical and spiritual realms was conceived very differently than it is today. It was widely believed that:

Angels could appear in human form.
Demons could assume apparent physical bodies.
Dreams could carry divine or demonic messages.
Illnesses could stem from spiritual causes.

Within this framework, experiences such as a waking feeling of heavy chest pressure, temporary paralysis, the sensation of an unseen presence, or intensely vivid erotic dreams were routinely interpreted as attacks by incubi or succubi.

Aquinas does not dismiss these events as mere illusions. He acknowledges that demons could manipulate human imagination and external senses to produce convincing perceptions. Crucially, he notes that demonic action acts upon the imagination and bodily humors rather than altering the core spiritual essence of the soul.

This idea aligned with medieval humorology, which held that physical imbalances affected emotions, dreams, and perceptions. While modern science attributes these phenomena to sleep paralysis and hypnagogic states, historically these medieval interpretations reflected the best medical and cosmological models available at the time.

PART IV — COMPARATIVE STUDY OF THE ORIGINS OF SUCCUBI AND INCUBI

Chapter VIII: Mesopotamia: The Cradle of Belief in Sexual Demons

When tracing the origins of sexual demons, most historians of religion point to ancient Mesopotamia as the earliest documented source. Between roughly 3000 and 2000 BCE, the Sumerians described spiritual entities associated with sleep, fertility, disease, and sexuality:

Lilû: A male wind spirit believed to visit women during sleep, exhibiting behavior strikingly similar to the later medieval incubus.
Ardat-Lili: A female spirit described in cuneiform texts as seducing men during sleep, causing erotic dreams, draining vital energy, and preventing marriage or fertility—a direct precursor to the succubus.
Lamashtu: A demonic figure linked to attacks on pregnant women, miscarriage, infant mortality, and childhood illness.
Gallû and Utukku: Broad classes of underworld or tormenting spirits.

Many Assyriologists contend that the European concept of the succubus derives in part from these Mesopotamian traditions, albeit transformed across millennia.

Chapter IX: Lilith: From Mesopotamia to Judaism

The evolution of Lilith is complex:

Mesopotamian Phase: "Lilitu" originally designated a class of female wind and night spirits, rather than a single individual figure.
Biblical Context: During the Babylonian Exile (6th century BCE), these concepts influenced Jewish folklore. In Isaiah 34:14, the Hebrew term Lilith appears (variously translated as "night creature" or "screech owl").
Medieval Jewish Folklore: In non-canonical works like the medieval Alphabet of Ben Sira, Lilith is presented as Adam’s first wife who refused submission, fled Eden, became the mother of demons, and spent nights seducing men and preying on newborns.

Though not part of the canonical Genesis text, the legend of Lilith heavily impacted Christian demonology and Western folklore.

Chapter X: The Watchers, the Nephilim, and Celestial-Human Unions

Another key tradition appears in the Book of Enoch (a Jewish text from the Second Temple period). It relates that 200 angels known as Watchers (Egrēgoroi) descended to Earth, took human wives, taught forbidden arts, and fathered giants known as the Nephilim.

This narrative directly contradicts Aquinas's Scholastic framework:

Book of Enoch: Describes literal physical unions between heavenly beings and human women.
Aquinas: Rejects physical angel-human reproduction on metaphysical grounds, reinterpreting ancient stories through Aristotelian physics.

PART V — SEXUAL DEMONS IN ANCIENT CIVILIZATIONS

Chapter XI: Ancient Greece: Lamia, Empusa, and Mormo

While ancient Greek mythology contains figures with functional similarities to succubi and incubi, there is no exact 1:1 equivalent.

Lamia (Λάμια): Originally a Libyan queen loved by Zeus, transformed by Hera's wrath into a monster that preyed on children and seduced young men. In late antiquity, her image merged with that of a night entity draining vital energy.
Empusa (Ἔμπουσα): Associated with Hecate, described as a shapeshifting entity that lured travelers in the form of a beautiful woman to feed on their flesh and vitality.
Mormo (Μορμώ): A figure associated with night terrors and nightmares, used to frighten children into obedience.

Unlike Aquinas's systematic theological approach, the Greeks understood these entities within an unsystematized mythological framework.

Chapter XII: Ancient Rome: The Strix and Night Spirits

Roman tradition developed the Strix (plural Striges)—demonic birds or transformed women that attacked sleeping people, sucked blood, preyed on infants, and drained vitality. These figures gradually merged into medieval folklore, directly influencing later legends of witches, vampires, and night demons.

Chapter XIII: Ancient Egypt and Zoroastrian Persia

Ancient Egypt: Lacked a direct succubus equivalent, but magical papyri detail fears of "restless dead" (akhu) disrupting intimacy, causing infertility, or tormenting the living through dreams.
Zoroastrian Persia: Pahlavi texts describe female daevas (demons) associated with lust and seduction. Scholars suggest Persian dualistic demonology influenced post-exilic Jewish and early Christian concepts of evil spirits.

PART VI — SUPERNATURAL SEXUAL ENTITIES IN EASTERN RELIGIONS

Chapter XIV: Islam: Jinn, Qarina, and Spirit Unions

Islam does not possess an official doctrine of succubi and incubi. However, Islamic theology and folklore recognize Jinn—beings created from "smokeless fire" possessing free will.

The Quran: Confirms Jinn can marry among themselves, but does not state they can impregnate humans.
Medieval Jurists: Debated claims of human-Jinn romantic or sexual contact; some dismissed them, while others treated them as spiritual disturbances.
The Qarina: Regional folklore speaks of the Qarina (a spirit companion) seducing men during sleep. This remains a matter of local folklore rather than universal Islamic dogma.

Chapter XV: Asia: India, China, and Japan

+---------------------------------------------------------------------------------------------------+
| Region      | Entity           | Primary Characteristics & Role                                   |
+-------------+------------------+------------------------------------------------------------------+
| India       | Yakshinis        | Nature spirits; can grant power or tempt ascetics in folklore.   |
|             | Apsaras          | Celestial nymphs; seduce sages/heroes; non-demonic.             |
|             | Vetalas          | Corpse-possessing spirits; associated with cemeteries.           |
+-------------+------------------+------------------------------------------------------------------+
| China       | Huli Jing        | Fox spirits; transform into women to drain vital energy (qi).    |
+-------------+------------------+------------------------------------------------------------------+
| Japan       | Kitsune / Yōkai  | Shapeshifting foxes/spirits; can marry humans or trick sleeping  |
|             |                  | men within Shinto/Buddhist folklore.                             |
+---------------------------------------------------------------------------------------------------+

A crucial distinction exists here: in Eastern traditions, these entities are often ambivalent or benevolent, whereas European medieval demonology categorizes succubi and incubi as exclusively demonic.

PART VII — THE HYBRID HYPOTHESIS: DID OFFSPRING OF SUCCUBI AND INCUBI EXIST?

Chapter XVI: The Great Medieval Debate

Medieval theologians wrestled with whether children could be born of demonic unions. This stemmed primarily from interpretations of Genesis 6:1–4 ("The sons of God saw that the daughters of humans were beautiful...").

Two main historical interpretations developed:

The Fallen Angel Interpretation (Book of Enoch, Early Church Fathers): "Sons of God" meant fallen angels who mated with women, producing the Nephilim.
The Sethite Interpretation (Saint Augustine, Aquinas): "Sons of God" referred to the righteous lineage of Seth, while "daughters of humans" meant the lineage of Cain.

Aquinas adopted the Sethite view, completely ruling out biological reproduction between spiritual beings and humans.

Chapter XVII: How Did the Legend of Demonic Offspring Persist?

In medieval Europe, children born with congenital deformities, extreme physical strength, gigantism, epilepsy, or severe mental illness were often rumored to be "children of the Devil." Lacking genetics, endocrinology, or neurology, communities attributed mysterious conditions to supernatural origins.

In world mythology, divine-human unions were common:

Greece: Heracles, Perseus, and Helen (fathered by Zeus).
India: Arjuna and Bhima (born of gods and human mothers in the Mahabharata).
Celtic Folklore: Intermarriage with the Aos Sí (fairies) resulting in extraordinary children.

Modern science clarifies that human reproduction strictly requires compatible human gametes; physical hybrids between humans and incorporeal entities are biologically impossible.

PART VIII — THE LEGACY OF AQUINAS AND MODERN SCIENCE

Chapter XVIII: Evolution of Demonology After Aquinas

Following Aquinas’s death in 1274, later medieval and early modern authors expanded on his writings, often removing his philosophical caution. Works like Johannes Nider's Formicarius (1435) and Heinrich Kramer’s Malleus Maleficarum (1487) popularized the idea of explicit sexual pacts with the Devil, citing Aquinas to grant their treatises academic authority.

                  ┌────────────────────────────────────────┐
                  │      MESOPOTAMIA (3000–2000 BCE)       │
                  │        Lilû / Ardat-Lili / Lamashtu    │
                  └──────────────────┬─────────────────────┘
                                     │
                                     ▼
                  ┌────────────────────────────────────────┐
                  │    JUDAISM & SECOND TEMPLE TEXTS       │
                  │    Book of Enoch / Lilith Tradition    │
                  └──────────────────┬─────────────────────┘
                                     │
                                     ▼
                  ┌────────────────────────────────────────┐
                  │     PATRISTIC PERIOD (300–500 CE)      │
                  │      St. Augustine (City of God)       │
                  └──────────────────┬─────────────────────┘
                                     │
                                     ▼
                  ┌────────────────────────────────────────┐
                  │   SCHOLASTICISM (13th Century CE)      │
                  │  St. Thomas Aquinas (Summa Theologiae) │
                  │  *Rejects direct demonic generation*   │
                  └──────────────────┬─────────────────────┘
                                     │
                                     ▼
                  ┌────────────────────────────────────────┐
                  │    EARLY MODERN DEMONOLOGY (15–17C)    │
                  │  Malleus Maleficarum / Jean Bodin      │
                  └────────────────────────────────────────┘

Chapter XIX: Modern Scientific Explanations

Contemporary neurology, psychology, and sleep medicine explain historical reports of incubi and succubi through natural phenomena:

Sleep Paralysis: REM sleep intrusion causing motor inhibition, chest pressure, and a sense of an evil presence.
Hypnagogic/Hypnopompic Hallucinations: Vivid sensory experiences occurring during sleep transitions.
Lucid & Erotic Dreaming: Endogenous brain activity creating realistic tactile and emotional experiences.
Cultural Framing: Subjective internal experiences interpreted through the prevailing religious or cultural framework of the era.

PART IX — COMPARATIVE SYNTHESIS ACROSS MYTHOLOGIES

Comparative Table of World Traditions

Tradition	Female Entity	Male Entity	Indirect/Direct Pregnancy Attributed	Shapeshifting / Apparent Body
Sumerian	Ardat-Lili	Lilû	Yes (in some myths)	Yes
Babylonian	Lilitu	Lilu	Yes	Yes
Medieval Jewish	Lilith	Demons	Yes (in folklore)	Not emphasized
Book of Enoch	—	Watchers	Yes (Direct)	No
Medieval Christian	Succubus	Incubus	Indirect only (Aquinas: transported human semen)	Yes (Assumed bodies)
Greco-Roman	Lamia / Strix	—	No	Yes
Islamic (Folklore)	Qarina	Certain Jinn	Disputed / No consensus	Yes
Hindu	Yakshini / Apsara	Yaksha	Mythological cases	Yes
Chinese	Huli Jing	Spirits	In legends	Yes
Japanese	Kitsune	Yōkai	In legends	Yes

Final Conclusion

The study of succubi and incubi reveals less about a theoretical "demonic biology" and far more about how human civilizations have sought to comprehend the mysteries of sleep, sexuality, fertility, and the unknown.

Saint Thomas Aquinas played a unique role in this history. Rather than accepting popular folklore uncritically, he subjected it to the rigorous logic and Aristotelian metaphysics of his era, strictly limiting the powers attributed to demonic forces. While his explanations reflect the cosmology of the 13th century, his work remains a landmark in the history of Western philosophy and medieval theology.

Complete Bibliography (ABNT NBR 6023:2018 Standard)

Primary Sources

AGOSTINHO. A Cidade de Deus. Tradução de Oscar Paes Leme. Petrópolis: Vozes, diversas edições.
AQUINO, Tomás de. Suma Teológica. Tradução de Alexandre Corrêa. São Paulo: Loyola, diversas edições.
AQUINAS, Thomas. Summa Theologiae. Latin-English Edition. Cambridge: Blackfriars; New York: McGraw-Hill, 1964–1981.
ARISTÓTELES. Da Geração dos Animais. São Paulo: Loyola.
ARISTÓTELES. Metafísica. São Paulo: Loyola, diversas edições.
A BÍBLIA SAGRADA. Tradução de João Ferreira de Almeida. Barueri: Sociedade Bíblica do Brasil.
BODIN, Jean. Démonomanie des Sorciers. Paris: Jacques du Puys, 1580.
CHARLES, R. H. (Ed.). The Book of Enoch. Oxford: Clarendon Press, 1912.
CHARLESWORTH, James H. (Org.). The Old Testament Pseudepigrapha. New York: Doubleday, 1983.
GUAZZO, Francesco Maria. Compendium Maleficarum. New York: Dover Publications.
ISIDORO DE SEVILHA. Etimologias. Madrid: Biblioteca de Autores Cristianos.
KRAMER, Samuel Noah (Org.). Sumerian Mythology. Philadelphia: University of Pennsylvania Press, 1961.
LAMBERT, W. G. Babylonian Creation Myths. Winona Lake: Eisenbrauns, 2013.
NIDER, Johannes. Formicarius. Augsburg, 1475.
PSEUDO-DIONÍSIO AREOPAGITA. Obras Completas. São Paulo: Paulus.
SPRENGER, Jacob; KRAMER, Heinrich. Malleus Maleficarum. Tradução moderna. São Paulo: Madras.

Ancient History and Mesopotamia

BLACK, Jeremy; GREEN, Anthony. Gods, Demons and Symbols of Ancient Mesopotamia. Austin: University of Texas Press, 1992.
BOTTÉRO, Jean. Mesopotâmia: A Escrita, a Razão e os Deuses. Lisboa: Edições 70.
DALLEY, Stephanie. Myths from Mesopotamia. Oxford: Oxford University Press, 2000.
JACOBSEN, Thorkild. The Treasures of Darkness. New Haven: Yale University Press, 1976.
KRAMER, Samuel Noah. History Begins at Sumer. Philadelphia: University of Pennsylvania Press, 1981.
LEICK, Gwendolyn. Mesopotamia: The Invention of the City. London: Penguin Books.

Ancient Judaism

PATAI, Raphael. The Hebrew Goddess. Detroit: Wayne State University Press.
SCHÄFER, Peter. Mirror of His Beauty: Feminine Images of God from the Bible to the Early Kabbalah. Princeton: Princeton University Press.
SCHÄFER, Peter. The Origins of Jewish Mysticism. Princeton: Princeton University Press.

Christianity and Demonology

CAVENDISH, Richard. The Black Arts. New York: Perigee Books.
CLARK, Stuart. Thinking with Demons. Oxford: Oxford University Press.
CORSINI, Eugênio. O Diabo na História. São Paulo: Paulus.
KIECKHEFER, Richard. Magic in the Middle Ages. Cambridge: Cambridge University Press.
RUSSELL, Jeffrey Burton. A History of Witchcraft. London: Thames & Hudson.
RUSSELL, Jeffrey Burton. Lucifer. Ithaca: Cornell University Press.
RUSSELL, Jeffrey Burton. Mephistopheles. Ithaca: Cornell University Press.
RUSSELL, Jeffrey Burton. Satan. Ithaca: Cornell University Press.
RUSSELL, Jeffrey Burton. The Devil: Perceptions of Evil from Antiquity to Primitive Christianity. Ithaca: Cornell University Press.

Medieval History

DUBY, Georges. A Idade Média. Rio de Janeiro: Jorge Zahar.
HUZINGA, Johan. O Declínio da Idade Média. São Paulo: Cosac Naify.
LE GOFF, Jacques. A Civilização do Ocidente Medieval. Lisboa: Editorial Estampa.
LE GOFF, Jacques. O Imaginário Medieval. Lisboa: Editorial Estampa.

History of Religions & Anthropology

CAMPBELL, Joseph. As Máscaras de Deus. São Paulo: Palas Athena.
CAMPBELL, Joseph. O Herói de Mil Faces. São Paulo: Pensamento.
ELIADE, Mircea. História das Crenças e das Ideias Religiosas. Rio de Janeiro: Zahar.
ELIADE, Mircea. O Sagrado e o Profano. São Paulo: Martins Fontes.
ELIADE, Mircea. Tratado de História das Religiões. São Paulo: Martins Fontes.
FRAZER, James George. O Ramo de Ouro. Rio de Janeiro: Guanabara.
LÉVI-STRAUSS, Claude. Antropologia Estrutural. Rio de Janeiro: Tempo Brasileiro.
LÉVI-STRAUSS, Claude. O Pensamento Selvagem. Campinas: Papirus.
MALINOWSKI, Bronislaw. Magia, Ciência e Religião. São Paulo: Perspectiva.

Neuroscience, Psychology & Sleep Medicine

CHEYNE, James Allan. Sleep Paralysis and the Structure of Waking-Nightmare Hallucinations. Dreaming, Washington, DC: American Psychological Association.
FREUD, Sigmund. A Interpretação dos Sonhos. São Paulo: Companhia das Letras.
HOBSON, J. Allan. Dreaming: An Introduction to the Science of Sleep. Oxford: Oxford University Press.
JUNG, Carl Gustav. Os Arquétipos e o Inconsciente Coletivo. Petrópolis: Vozes.
JUNG, Carl Gustav. Símbolos da Transformação. Petrópolis: Vozes.
MAHOWALD, Mark W.; SCHENCK, Carlos H. Insights from Studying Human Sleep Disorders. Nature.

Comparative Mythology & Folklore

BRIGGS, Katharine. An Encyclopedia of Fairies. New York: Pantheon Books.
BULFINCH, Thomas. O Livro de Ouro da Mitologia. Rio de Janeiro: Ediouro.
GRAVES, Robert. Os Mitos Gregos. Rio de Janeiro: Nova Fronteira.
HAMILTON, Edith. Mitologia. São Paulo: Martins Fontes.
KEIGHTLEY, Thomas. The Fairy Mythology. London: Bell & Daldy.