Lilith is one of the most contested figures in the history of religion — a character whose origins are genuinely obscure, whose development across Jewish tradition is complex and contradictory, and whose modern significance as a symbol of feminine autonomy, rejected womanhood and dangerous power is entirely out of proportion to her brief and ambiguous presence in the canonical Hebrew Bible. She appears by name exactly once in the entire Hebrew Bible — in Isaiah 34:14, in a list of desert creatures that will inhabit the desolate ruins of Edom. The rich tradition of Lilith as Adam's first wife, as the mother of demons, as the night creature who kills infants and seduces men — all of this is later elaboration on a single word in a single verse.
The most likely origin of Lilith is the Babylonian Lilitu (also Ardat Lili) — a class of female wind and storm demons in Mesopotamian demonology, associated with illness, infant death and the dangers of the night. The Sumerian ki-sikil-lil-la-ke (sometimes translated as "the Lilith") appears in the Gilgamesh cycle, inhabiting a tree that Inanna wants to use for a throne before being driven out by a hero. The connection between the Hebrew lilit and the Babylonian lilitu is supported by the root lil (wind/air in Sumerian) and by the consistent association with nocturnal danger in both traditions.
The single Hebrew Bible verse (Isaiah 34:14) describes the desolation of Edom: "The desert owl and the screech owl will possess it; the great owl and the raven will nest there... there the night creature (lilit) will alight and find for herself a resting place." Whether the verse describes a demon, a specific owl species or simply a night creature is contested among scholars. Most modern translations render lilit as "screech owl" or "night owl" rather than "Lilith" specifically.
The Alpha-Bet of Ben Sira: the version of Lilith most people know — Adam's first wife who refused to lie beneath him, cited her equal creation from the same earth as grounds for equality, and left Eden when Adam refused to acknowledge this equality — comes primarily from a medieval Jewish text called the Alphabet of Ben Sira, composed sometime between the 7th and 11th centuries CE. In this account, Lilith refuses subordination, speaks the ineffable name of God, and flies away to the Red Sea, where she becomes the mother of demons (lilin). Three angels are sent to bring her back; she refuses; the deal struck is that one hundred of her demon children will die each day, and in revenge she will kill human infants unless protected by amulets bearing the three angels' names. This is the founding text of the Lilith-as-first-wife tradition — it is not ancient, not canonical and not a straightforward piece of religious literature (the Alphabet of Ben Sira is a deliberately provocative and satirical text).
The Lilith tradition addresses a genuine textual puzzle in Genesis. Genesis 1:27 states: "So God created mankind in his own image, in the image of God he created them; male and female he created them." Genesis 2:21-22 then describes God creating woman from Adam's rib. These appear to be two different creation accounts — the first describing a simultaneous creation of male and female, the second describing the later creation of Eve from Adam. Rabbinic tradition noticed this inconsistency and proposed a resolution: the woman created simultaneously with Adam in Genesis 1 was a different woman — Lilith — and Eve was the second, later woman created in the Genesis 2 account.
This reading is textually inventive rather than textually obvious, but it has the advantage of resolving the contradiction between the two creation accounts by making them sequential rather than contradictory. The Lilith tradition is, among other things, a piece of rabbinic biblical criticism — an attempt to make the Genesis narrative internally consistent.