Definitely worth having. It has countless really great thoughts on film composition from the maestro himself. The book is a translation of film music seminars that were given by Miceli and Morricone between 1991 and 2000. When Morricone is speaking in particular, it is incredibly illuminating as to what his process is, what his beliefs are, and what he strives for in his film music. I've already quoted it in a few places on my blog when I was discussing Morricone's themes for Once Upon a Time in the West.
To me the book is worth it just for Morricone's contributions.
Loren, you write that it is full of sheet music examples, yet one amazon reviewer says it doesn't contain any single one! from browsing the preview, this must be the case. So, i was wondering why you wrote that..