Osprey's examination of the first American amphibious assault of World War II (1939-1945). On what was a virtually unheard of Pacific island, the United States shattered the myth of Japanese invincibility, as the US Marines and Army halted the apparently irresistible Japanese advance in its tracks. Over 30,000 American and Japanese casualties were suffered in five months of bitter fighting. From the ranks of the units that contested this campaign a seasoned fighting force of US veterans was created that would, island by island, sweep the Japanese back across the Pacific.