In warfare the battles grab most of our attention. But there is a secret history to every war; a hidden world of spies, double agents, assassins and saboteurs. Secret History: World War I explores how each side tried to keep secrets from the enemy, while at the same time trying to break their codes and disrupt their missions. From invisible ink and secret codes, to propaganda and battle tactics, this book covers all of the main ways each side tried to outwit the other - and win the war.

Secret History is a series of books exploring the six major conflicts of the 20th century.