I really like this book because it's not one of these "how to get famous and rich with your music" self-help books. Rather, it's a take on the music industry from the singer-songwriter perspective. I found many tips in there, e.g. how to turn fragments of lyrics into an actual song (and how to decide which will remain a fragment forever). Another great feature are the extensive quotes by singer-songwriters (Joni Mitchell, James Taylor...) that explain how songwriting works.
The tips in the book have been a great source for my songwriting and I have reviewed a few chapters of the book in the past ([...]), showing how I incorporated the tips into my own writing.
I highly recommend the book.