Volume Four of this impressive series covers the same basic topics as the three previous volumes, but from the exclusive standpoint of the .50 caliber Browning, which has been in continuous service longer than any other weapon in the U.S. arsenal, and is still in use today in the inventories of 86 countries worldwide.

2008 marks the 90th anniversary of John Browning's first .50 caliber prototype, which, after a shaky start, came into its own with the introduction of the M2 "universal receiver" in 1933. A total of eight prime contractors - three of them divisions of the General Motors Corporation which had never produced a firearm of any kind before - manufactured nearly two million .50 caliber Brownings, of six basic types, during WWII.

By the late 1970s U.S. Army requirements had exceeded available stocks, and today a number of modern contractors are again producing standard and enhanced versions of the venerable M2 in the U.S., Britain and elsewhere.