Music Books cover a wide range of titles, techniques and instruments. There are titles that will teach you to play an instrument from scratch to those that will have you playing like your favourite artist in no time at all.
As a musician you will want to play specific songs and you will find the song in a music book in the particular format you need whether it be tab for guitar or piano pieces. Some books will have the song shown in multi-format, covering all the information you need to play it on any instrument.
Many famous artists have also produced their own books showing the notation for their songs and these are usually backed up with a CD to aid your practice and technique.