America's Pursuit of Precision Bombing, 1910-1945 offers a meticulously researched and lively account of the development of the renowned Norden bombsight and its curious relationship to American strategic bombing doctrine and practice. The Norden bombsight was the United States' first "secret weapon," ultimately the best optical bombsight produced anywhere. It was America's most expensive secret program prior to the Manhattan Project. Its development was supported not by the Army Air Corps, but by the U.S. Navy's Bureau of Ordnance. The work spanned nearly twenty years in absolute secrecy and in clear contravention of military procurement policies and statute law.
Carl Norden, its brilliant and eccentric inventor, was a Dutch national who never became an American citizen. He took little interest in the day-to-day operations of the firm that bore his name, doing the bulk of his design work at his mother's home in Switzerland, even in 1939-40. His designs were sent back to the United States via sealed diplomatic pouch. Complications arose in World War II when the U.S. Navy retained three-quarters of the instruments despite having little need for them. Also, as production shifted from hand-crafting to mass production, the accuracy of the bombsights fell.
McFarland's exhaustive account remains a definitive and authoritative history of this fascinating piece of technology.