Faking is the art of being able to play a tune without being able to read music. The original fakebooks were hand-written chord charts, notation, and lyrics that allowed you to get through someone else's tunes in the days of old, including Nashville notation and tab systems - but they didn't have much "real music" in them. They were "fake" in the sense that the player did not have to "read the dots". In jazz/swing times, lots of band members couldn't read music, but the band could fake around this as long as there were not too many of them - the practical limit with a jazz band is 8-9 members, above this all the horns and reeds have to be readers, below this they can usually "riff through the choruses". The things that are sold nowadays are, as detailed above, just enough to get by on, but they differ from the old hand-written books in that they have musical notation.In jazz circles the art of getting through a tune you don't know without rehearsal is called "busking", and in England books such as those described above are often described as "Buskers' Books". The fact that publishers describe them as Fake Books only reflects what musicians have known for years - publishers are grasping businessmen who will say anything to make money.