I just read a book called George Washington Spymaster. It was written by Thomas B Allen. It was about how George Washington out spied the British during the American Revolution.
The book talks about the methods the American spies used to trick the British during the Revolutionary War. One instance was when the Americans leaked fake messages to known British spies about things like where the American Army was going or the size of it. One American spy was a lady nicknamed Old Mom Rinker. She passed messages along by sitting on the edge of a cliff at night and dropping a yarn ball with a message in it down to other people to be carried along to an American patrol.
Stuff That Jack Built 