It's not a great book -- it's one of those ones you get on the Barnes and Nobel Bargain racks for $5.99 -- but it's a good overview. The text and illustrations are great, but the color profiles at the end or weird -- they should be drawn to a common scale, and the specs don't include armament for most of the vehicles, which is a kinda important part of an AFV's specifications.
Not very useful to model-builders (not enough color profiles with no unit assignments or dates), but, like I said, a good overview.