Nelson MacPherson 
American Intelligence in War-time London [PDF ebook] 
The Story of the OSS

Based on OSS records only recently released to US National Archives, and on evidence from British archival sources, this is a thoroughly researched study of the Office of Strategic Services in London. The OSS was a critical liaison and operational outpost for American intelligence during World War II. Dr Mac Pherson puts the activities of the OSS into the larger context of the Anglo-American relationship and the various aspects of intelligence theory, while examining how a modern American intelligence capability evolved.