ISBN 0531037746 - First, remember that "future" is relative to the time the book was published - 1984. This is obvious on page 19, where the book discusses the need for Western navies to keep an eye on Russian subs. Other than being slightly dated, the book has some interesting info. And don't believe the indication that this book is for ages 4-8. "Ballast" is hard enough to explain to 10 year olds, forget about 4 year olds!
From the man-powered HL Hunley to the submarines of the 1980s, this book does a fairly good job of explaining the history of subs, some of the basics of how a submarine works, and how it's possible for people to be on them for a long period of time. For more current information, this isn't the book, but what it covers, it covers well. Some of the more unusual subs ever created have their own chapter, which is the most interesting part of the book to me - I would have liked more information on those.
The photos, some real pictures, some illustrations, are nicely numbered and explained. It's interesting that the cutaway photo of a sub doesn't show, just indicates the presence of, the nuclear reactor - but I think it would have been nice to explain why it isn't shown. All in all, the book is a good resource for some info, but if you're using it for a report, make sure you use it along with something more current!