Title: Invisible Ink
Author: John A Nagy
Nagy, John A. (2011). Invisible Ink: Spycraft of The American Revolution. Yardley, PA : Westholme Publishing
Spies–United States–History–18th century.
Spies–Great Britain–History–18th century.
Espionage–United States–History–18th century.
Espionage–Great Britain–History–18th century.
United States–History–Revolution, 1775-1783–Secret service.
United States–History–Revolution, 1775-1783–Cryptography.
United States–History–Revolution, 1775-1783–Military intelligence.
Date Posted: October 3, 2017
Review by John Resch
Despite John A. Nagy’s claim that “George Washington’s better military application of the intelligence gathered and disinformation dispensed proved key to the eventual American victory,” Invisible Ink is not a monograph that develops that thesis in a systematic manner (p. xvi). Invisible Ink is composed of three distinct sections that many readers of spying and intelligence gathering generally, and specifically during the American Revolution, will consult with profit.
The first section consists of chapters on techniques of spycraft. It begins with examples of codes and ciphers such as those used by the Spartans, Charlemagne, and Thomas Jefferson in his letters to conceal his courtship of Rebecca Burwell. Other chapters in this short section illustrate various techniques, such as the use of “masks” to reveal the hidden message in a harmless-looking document, and the invention and use of invisible ink.
The main section of the book continues to be organized around techniques, such as the dead drop, to secretly convey information. Nagy illustrates them through episodes in the American Revolution. Readers of Invisible Ink should complement these chapters by viewing Spy Letters of the American Revolution online at the University of Michigan’s William L. Clements Library. The site contains letters (some cited by Nagy), maps of spy routes, techniques, and stories of various spies, such as Robert Townsend and Abraham Woodhull’s group, known as the Culper spy ring. Nagy’s account of the Culper ring is particularly instructive in showing the amateurish spies and unreliable information that George Washington was wise to question. Leaders were skeptical about military intelligence—much of it little more than gossip—passed between lines by travelers, smugglers, and those operating under a flag of truce. Deception, disinformation, and double agents deflated the value of military intelligence. Nevertheless, Nagy speculates that Gen. William Howe was influenced by the receipt of Washington’s deceptive fitness report on the Continental army at Valley Forge to believe “he would face much stiffer resistance then would occur if he chose to attack the American Army at Morristown” (p. 172).
The last section of the book is organized differently. Nagy applies five elements that compose a “deceptive battle plan” (p. 218). He illustrates each element with episodes from World War II, the 1991 Iraq War, and the American-French campaign against Gen. Charles Cornwallis at Yorktown. Nagy credits Washington’s spycraft for keeping Gen. Henry Clinton in New York and not coming to Cornwallis’s aid, giving that factor more credence for the victory at Yorktown than is conventional. It is disappointing that the conclusion of Invisible Ink is a one-page aphorism that old spycraft techniques continue in the twenty-first century in the form of new technology rather than a reflection on where and how intelligence gathering played a key role in winning the War for Independence.
 John Resh, Journal of American History (97, 4, March 1, 2011). Accessed at https://academic.oup.com/jah/article-lookup/doi/10.1093/jahist/jaq013.