This is the fourth and final volume in Collector Grade's monumental series on the Browning machine gun.

Volume One, subtitled Rifle Caliber Brownings in U.S. Service, published in 2005, covers the invention, development and manufacturing history of all models of rifle caliber Brownings in the United States, and their use by U.S. forces in two World Wars and Korea.

Volume Two, Rifle Caliber Brownings Abroad, published in 2006, covers the offshore production and use of rifle caliber Brownings in 35 other countries.

Volume Three, subtitled Supporting the Rifle Caliber Brownings, contains expert, in depth coverage of an exhaustive number of important technical topics, useful for shooters and collectors alike.

Volume Four 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.