It’s a pretty good compendium of compositional ideas, approaches, and tools. I’ll probably be keeping it on the shelf as an idea book and something to draw pedagogical approaches from for my own students. Definitely presupposes some skill in reading and writing music, though not much more than that. The amount of theory you absorbed in piano lessons or whatever is probably sufficient and you could look stuff up as you need it, I think. There was a huge mistake on page 151 where he gives the wrong definition for retrograde inversion, so know that if you get that far. That was the only glaring error that I happened to notice, but several sections I didn’t read in detail (I’m not going to improve my counterpoint with the presentation in this book, that’s for sure.) The section on orchestration is basically a cheat sheet on the orchestral instruments. I’ll still be reaching for my copy of Adler when I need to look something up, but if this is the only resource you have, you could do worse. Very limited presentation of 20th-century trends outside of tonal music, and a very limited presentation of songwriting if that’s your interest. Every chapter has lots of assignments and examples. On the whole, seems like a pretty good book to start with, but nothing especially useful here for anyone who’s been writing music for a while.