Originally invented by Brig. General John T. Thompson in 1918, the Thompson Submachine Gun was envisioned as a "one-man, hand-held machine gun" that would bring an end to WWI's entrenched stalemate. The air-cooled, recoil-operated, magazine-fed "trench sweeper" weighed less than 16 pounds (when equipped with a 50-cartridge magazine) and could be used for both automatic and semi-automatic fire. Although the weapon debuted after WWI came to an end, the Thompson was quickly adopted by the Marine Corps, FBI, and by the general public - including by organized crime. During the Prohibition Era the "Chicago Piano" or "Chicago Typewriter" became a mafia favorite due to its high rate of fire and large magazine capacity. During WWII, the "Tommy Gun" was widely fielded by the U.S. armed forces, with over 1.5 million produced by the end of the conflict. The main models in production were the M1928A1, M1 and M1A1. Originally published in December, 1941, this basic field manual was standard issue for U.S. Army personnel. It features a chapter on weapon mechanics with sections on weapon assembly and disassembly, care and cleaning, spare parts, functioning, safety precautions, and a primer on ammunition. It also includes chapters on technique of fire, marksmanship from a moving vehicle, marksmanship against air and ground targets, and advice to instructors. This high-quality reproduction presents the manual in its entirety. Although slightly reformatted, care has been to preserve the integrity of the text.