LOTR many times.

The New York Trilogy by Paul Auster. My favourite book by a mile. Deeper than a very deep bit of the briny ocean deep.

On a musical note, Last Night's Fun by Ciaran Curran is an excellent book about Irish traditional music. Even though I was not born into the tradition I have played the music for years, and many people will recognise some of the observations and philosophy in this fine tome.