Doom Bible

[Kage No Shujin]

What is the Doom Bible exactly?

[scwiba]

The early plan for Doom by Tom Hall. Deeper story, different characters, more realistic levels, etc.

http://5years.doomworld.com/doombible/

[Coopersville]

Wikipedia explains it pretty well, but I'd also recommend that you search the Doom Wiki before creating any more rubbish Doom-related threads. The Doomworld FAQ would be a good read, too.