teitetua
When I first started researching Lilith about ten years ago, the Wiki entry was no more than a stubb. I'm quite surprised it's been a bit more populated recently, but it's not thorough.
As LRD states, there is no such thing as an original Bible - the version most commonly used now of the Old Testament was the work of many scholars over hundreds of years. Genesis at minimum was written in 500 BC, but it's very contradictory depending on which modern faith group you want to believe.
The first reference to Lilith features in the Epic of Gilgamesh which was written in approximately 1800 BC, though the main text that is preserved dates to the 1300 BC; both of which are significantly older than any of the core Hebraic texts.
It's not a flight of fancy or a pieced together fragment of a story; the Lilith myth pervades through multiple faiths of the central, middle and near East over a period of more than 4000 years.
There are stone statues of her, that carbon date correctly back through the Mesopotamian and Akkadian eras, as well as thousands of pages of writings through the various Hebraic periods, most significantly through the Zoharic period.
I don't believe she was ever real, but I don't believe God is, or Jesus or Shekinah or Eve, but I do believe that Lilith was a cornerstone of the development of what we know refer to as Christianity and find it remarkable and very pertinent to feminism that she has been written out of our cultural and religious history.
(apologies if I come off as ranty, but this is a subject I've rather passionate about!) 