To gain the upper hand in conflict the ability to know what your enemy is planning is vital. Separating myth from reality, the Enemy Within traces the history of espionage from its development in ancient times through to the end of the Cold War and beyond, shedding light on the clandestine activities that have so often tipped the balance in times of war. From the Monkey hanged as a spy during the Napoleonic wars to the British Double Cross Committee in World War II, this journey through the history of espionage shows us that be they thrill seekers or madmen, fanatics or tricksters no two spies are alike and their fascinating stories are fraught with danger and intrigue.