A while back, I was approached and asked to review a book that was still in progress. I read through it and made some specific comments and suggestions. Now, the final version of the book is complete and has been published. Not only were my suggestions taken, but I am privileged to have a quote of mine in use on the first page, just inside the cover. I liked the book when I read the earlier draft, and I like it even better now.
If you get a chance, take a look and see what you think.
He also has a website dedicated to tips and tricks for Ubuntu at ubuntukungfu.org.