The “On-The-Roof Gang” was a group 150 Navy and 26 Marine Corps enlisted radio operators who were trained to copy Japanese telegraphic code and to intercept and analyze Japanese Naval radio messages. In the years 1921 through 1927, several U.S. Navy and Marine Corps personnel taught themselves to copy the Japanese code and passed these skills informally to many of their shipmates. The intelligence value of the information they collected was recognized, and, under the auspices of the U.S. Navy Department of Naval Communications, formal training was developed and implemented in 1928. Through 1941, this training took place in a specially constructed block house on the roof of the old Main Navy Building in Washington, DC. The graduates of this training became known as the “On-The-Roof Gang” and were posted throughout the Pacific Theater at various intercept stations and aboard ship. They were experts primarily in the collection of Japanese radio communication, but also developed cryptanalysis, traffic analysis, and direction finding into a fine art as well. Most of the On-The-Roof Gang went on to perform Radio Intelligence during World War II and are credited with helping to turn the tide at the naval battles of Coral Sea and Midway. However, in my research over the past 10+ years, I have found that there is much more to the story of the On-The-Roof Gang, and I feel honored to be able to share their stories with you over the coming weeks and months.