This is a wonderful first reference text from Julian Sprung. Well set out and communicates the necessary information in an undestandable way. A word of advice, don't get this text in a hardcover version as the pages are poorly bound and Amazon's inability to adequate package the book results in damaged corners. Why pay more to get damaged goods and the Amazon run-around?
After 30+ years as a salt water enthusiast, I can easily say thAt this book answers the majority of questions about the proper ways to keep inverts alive and well in a home aquarium setting.
I highly recommend this book-it will save you frustration and money! In addition, the numerous photos will aid you in identification and also your decision making for invert purchases.
BUY IT!
No false advertisement here

This book is something you can browse to plan aquarium inhabitants, and take with you to the store to get some quick facts on species you come by. It has plenty of great pictures to help ID animals. Of course, some animals such as snails or hermits are so similar and have so many variations that you may have a hard time, but you should still get some important general info. More pictures of variations would be a welcome addition in a future volume, but don't let me give you the idea there aren't already loads of great ones.
This is a good companion to his "Corals - A quick reference guide", as it covers the other half of the spectrum including some anemones, mushroom corals, and zoanthids readers may have expected to find in the other volume...
As the name states, this is "a quick reference guide", so don't expect in depth comprehensiveness / knowledge on any one area or organism. As long as you realize that, you won't be upset. I very frequently consult this book.