The Allied invasion of Sicily in July and August 1943, codenamed Operation Husky, was the largest combined amphibious operation in history. While it was successful and led to the fall of the Mussolini regime, it resulted in tough and sometimes costly lessons in warfare that would prove valuable in the planning and execution of Operation Overlord the following June. Kevin Weddle, professor emeritus of military theory and strategy at the U.S. Army War College, examines a critically important operation that played a major, but often forgotten role, in the Allies’ ultimate success in World War II in Europe.