Cassandra Schumacher 
Code Breakers and Spies of the American Revolution [PDF ebook] 

The American Revolution was a war fought by soldiers and won by spies. The Continental Army did not stand a chance against the British superpower, but with accurate and fast intelligence, General George Washington was able to gain an advantage and win the war. From early intrigue in France to the Culper Spy Ring in New York, this book explores it all. Readers will learn how the first American spies turned the tides of the war and helped win independence.