CHAIN OF COMMAND

UST FOUR U.S. NAVY MEN have worn the five-star insignia of a full admiral. Among their ranks, William D. Leahy is the least well-known—and, as Phillips Payson O’Brien argues in a new biography, the most underappreciated. Leahy did not command the U.S. Navy like Ernest J. King, direct naval operations in the Pacific like Chester Nimitz, or win battles