Logistics, loh JIHS tihks, is the practical art of providing and maintaining soldiers, equipment, and supplies for military operations. Modern armies armed with complex weapons and equipment require tremendous logistical effort to put them into battle and keep them there. For example, almost half the total strength of the United States Army in World War II (1939-1945) had to provide logistic support for the other half that came in direct contact with the enemy. One out of four men in a combat division performed duties related to logistics, such as supply and administration.