Fred Crismon has turned a lifetime of photographing military vehicles and rummaging through archives into a pair of superb reference books, "U.S. Military Tracked Vehicles," and its companion, "U.S. Military Wheeled Vehicles" (he also published a third, paperback volume recently that brings the series up to date). There are hundreds of photos of all types of armored and unarmored vehicles. If you are just interested in the famous vehicles, then this book is only slightly useful — for instance, there are much better references on the Sherman tank available. But for an overview of all vehicles, including obscure machines that never served in frontline combat, this is a unique reference. Where else could you find photos of arctic snow tractors of the 1950's, or experimental light tanks of the 1930's, or airfield tractors of the US Air Force? Most types or subtypes receive a long paragraph and a single b&w photo. Should be in the library of every serious military vehicle historian.