Frank Schwede 
Reconnaissance Planes Since 1945 [PDF ebook] 

Reconnaissance aircraft have always been the spearhead of the various air forces, helping to provide the basis for any further military operations. At the time of the Cold War and before the satellite era, the use of reconnaissance aircraft reached its zenith, as the warring nations were determined to know what was happening on the other side. Consequently, powerful aircraft emerged during this time, especially in terms of deployment altitude, speed and flight time; achievements which have been largely unrecognised until now.