fake books give you the chord progression and melody to a song so you can "fake" your way through it. Generally intros, endings, and solo's are not given inless there an integral part of the song.
The illegal jazz fakebook was created by a bunch of Berkelee students in the early seventies (?)
There is no copyrights issued so the composers are not compensated for there work. On the plus side, the illegal fakebook has become so popular that most of the tunes in there are considered standards and have been immortalized, had they not been published many of these tunes may have been forgotten about or passed over.