According to you, how operate the spies changed the course of history?This book will explore the lives and times of the ten greatest spies, or spy networks, in history. Some have taken on legendary status, such as Mata Hari, the World War One-era exotic dancer, and courtesan who shared the bed chambers of so many French and German officers that she couldn't help but become a double agent. Others spied for pure ideological conviction, such as George Koval, the Iowa-born spy who leaked American nuclear secrets to the Soviet Union, accelerating Russia's nuclear program by years and making the Cold War arm's race possible. Still, others have attained a near-religious level of adoration -- Nathan Hale, the Revolutionary War-era spy, had a very short career but became America's first martyr and a treasured national symbol.