Some of the best of this hopscotch history of sub warfare is the early review of those daring young men in their submersible machines. Since the 16th century men have been designing propelled devices for traveling underwater, and James I is said to have ridden under the Thames in one. In 1776 a U.S. sub, Turtle, attacked a British flagship offshore Manhattan, but the submariner could not bore through the victim's copper-bottomed hull. It took our Civil War for the technological big push, which was followed by invention of the torpedo--essentially the same torpedo we have today. Real proof of the submarine's terrifying effectiveness came with the German U-boat packs that sent so much Allied tonnage to the bottom in World War I. During WWII the U-Boats in the North Atlantic, attacking Allied shipping and lend-lease to Britain, were not fully effective in their short daylight hours until the advent of radar. Several submarine successes on both sides are sketched into the text, and the British patrols that secured the Mediterranean, cutting Rommel's life-line to North Africa, are more heavily detailed. Though this is a British book, Uncle Sam's subs in the Japanese-held South Pacific round out the brief chronicle.