I just finished reading most of this book. As background, I have rebuilt several axles before, but wanted a manual for future axle builds and to keep around the garage for reference information. I think the Amazon book description above gives a pretty fair summary of the content, but I was still pretty surprised with the amount of information in this book, as it's pretty comprehensive.
The meat of the book is the steps on how to rebuild an axle and differential, but there is also a lot of other background information on topics like selecting your parts, calculating your gear ratio, and aftermarket performance part options. There are plenty of photos and illustrations to help visualize the parts and how they function and assemble. This is important to me, as I'm the type of person that likes to both read the information and see a picture to reinforce it. Also, the technical information is explained in an easy-to-understand way, with lots of examples. I think this would be a good starting point for anyone who is preparing to build their next high performance axle.
Bottom line - I'd recommend it.