Readers of Cartoonist Roy Crane's comic strip "Buz Sawyer" were introduced back in 1966 to an outfit called the U.S. Navy Seals (for Sea, Air and Land), an elite bunch of commandos with which Buz performed deeds of derring-do in Viet Nam. It may have seemed like rousing fantasy to readers, but the fact was that just such an outfit was operating in Viet Nam—where its presence was one of the most closely kept secrets of the war.* Only now, in fact, when the Communists themselves have learned of the Seals' presence the hard way, has the Navy begun to dis...