On 1 September 1939, German armored columns and attack aircraft crossed the Polish border on a broad front and World War II began. Within days most of Europe was deeply involved in the conflict as nations took side for and against Germany and its leader, Adolph Hitler, according to their history, alliances, and self-interest. Soviet Russia, a natural enemy of Germany's eastward expansion, became a wary partner in Poland's quick defeat and subsequent partition in order to maintain a buffer zone against the German advance. Inevitably, however, after German successes in the west and the fall of France, Holland, and Belgium, in 1940, Hitler attacked Russia, in 1941. In the United States, a week after the fighting in Poland started, President Franklin D. Roosevelt declared a limited national emergency, a move which, among other measures authorized the recall to active duty of retired Armed Forces regulars. Even before this declaration, in keeping with the temper of the times, the President also stated that the country would remain neutral in the new European war. During the next two years, however, the United States increasingly shifted from a stance of public neutrality to one of preparation for possible war and quite open support of the beleaguered nation allied against Germany. This book addresses the Marine Corps' preparation for World War II.