Marty Cagan says his book is limited to the IT industry but he underestimates it: I found most of the principles laid out to apply to my industry (chemicals). What I like the most is the accent he puts on the importance of customer experience with the product.
This book is a "must read" for every product manager.
With its fine granular structure, the book can be read all at once, or used as a reference in order to clarify questions such as "What are differences in roles between product management and design?" or "How to assess product opportunities?".
Having worked myself in different roles in the Internet as product manager & consultant in large corporations and start-ups with enterprise and consumer software, I find that Marty's analysis and recommendations hit the bull's eye.
A clear recommendation - Marty, thanks for this very fine book!