As the subject suggests, this book should be titled Ultimate. Essential, yes, but where this book departs from the others on the subject is the chapter on Behavior, describing how to spot the critter's habits and make that part of the shot. Also excellent is the "How to Wow" chapter. Borrowing a page from Larry and Denise's seminars, this chapter explains how to add the "Pizzazz" that separates a good photo from an award winner. All the technical information is right on and very up to date with current digital technology as well as traditional film technics. Every underwater photographer needs this book!