This book in reality have very litttle to do with Agility. While the word is scattered around the book, then contents are sound advice to any programmer in any project or development team!
Heck, I recognize stuff in here from the 80-ties, so very little is new under the sun. But it is in fact a very good and compact guidebook to good practices and very easy to reread and apply to different situations.
If you are a programmer (aspiring or senior) you can learn something from this book.