At the beginning of World War II, Prince Junio Valerio Borghese, dashing Italian nobleman, assembled the famous Decima MAS naval unit-the first modern naval commando squad. Borghese's "frogmen" were trained to fight undercover and underwater with small submarines and assault boats armed with a variety of destructive torpedoes. The covert tactics he and the Decima MAS developed, including the use of midget submarines, secret nighttime operations, and...