The Thompson submachine gun, also known as the Tommy gun, gained almost iconic status during the 20th century. It had an unusual beginning, as it was developed in the last days of World War I as a 'machine gun that can be handled by one man.' The war ended before the first prototypes could be sent to Europe, but once the M1921 Thompson officially went into production, it was used by criminals operating in Chicago and New York during the 1920s. With the police becoming increasingly disarmed, they too had to arm themselves with the Tommy gun.

It quickly became a part of Hollywood, and by the end of the 1930s, it would likely have faded from memory if history had not intervened. As the United States entered World War II, there was an urgent need to supply and equip a massive military force. The Thompson submachine gun began a second career as part of the U.S. military. It also became the weapon of choice for a small group of British commandos as they carried out several daring raids deep into occupied Europe.