Then-Captain Hitt, just before World War I, authored The Manual for the Solution of Military Ciphers. Published in 1916, this was the first work of its kind in the United States in 100 years and laid the foundation for the nation's impressive cryptologic achievements during the 20th century.

Born in 1878, Colonel Hitt attended Purdue University, but enlisted in the Army during the Spanish American War. In 1899, he received a commission as an infantry officer and was posted to the Philippines. 

Recognizing the importance of new communications methods, Colonel Hitt applied for a two-year detail to the Signal Corps. While teaching at the Army Signal School, he researched and wrote his groundbreaking manual on military ciphers. 

Colonel Hitt, knowing the U.S. Army field cipher was insecure, designed a more secure system as a replacement in 1914. In 1917, the Signal Corps widely adapted Colonel Hitt's cylindrical device, and it remained in service the better part of three decades. 

During the period of tension with Mexico, which culminated in Pershing's Punitive Expedition, Colonel Hitt and his wife, Genevieve Young Hitt, "moonlighted" to solve intercepted messages. He gained a well-deserved reputation as one of the Army's most talented codebreakers, and General Pershing selected him to be a member of his staff when the American Expeditionary Force (AEF) deployed to France in 1917.

As a Senior Signal Officer with the AEF during World War I, Colonel Hitt oversaw the compilation of a highly effective code that replaced an awkwardly translated French coding system that was being used by American forces. He also supervised units that intercepted sensitive German communications with impressive results.

In retirement during the 1940s, he was an informal liaison between the Army and members of the American Cryptogram Association but was anxious to serve in the war. Colonel Hitt returned to active duty from 1940 to 1944 as a corps area Signal Officer.

At a time when the nation had no formal cryptologic service, Parker Hitt's innovative work documented concepts and principles that would be used to protect U.S. military communications for decades. His work also directly influenced William and Elizebeth Friedman, who referred to him as the "father of modern American cryptology."

Colonel Parker Hitt died in March 2, 1971 at age 93.