United States Cryptologic History A Priceless Advantage U.S. Navy Communications Intelligence and the Battles of Coral Sea, Midway, and the Aleutians series IV: World War II | Volume 5 | 2017 Center for Cryptologic History Frederick D. Parker retired from NSA in 1984 after thirty-two years of service. Following his retirement, he worked as a reemployed annuitant and volunteer in the Center for Cryptologic History. Mr. Parker served in the U.S. Marine Corps from 1943 to 1945 and from 1950 to 1952. He holds a B.S. from the Georgetown University School of Foreign Service. This publication presents a historical perspective for informational and educational purposes, is the result of independent research, and does not necessarily reflect a position of NSA/CSS or any other U.S. govern- ment entity. This publication is distributed free by the National Security Agency. If you would like additional copies, please email
[email protected] or write to: Center for Cryptologic History National Security Agency 9800 Savage Road, Suite 6886 Fort George G. Meade, MD 20755 Cover: (l to r) Admiral Isoroku Yamamoto, Commander in Chief, Japanese Combined Fleet, 1942; aircraft preparing for launch on the USS Enterprise during the Battle of Midway on 4 June 1942 with the USS Pensacola and a destroyer in distance; and Admiral Chester W. Nimitz, Commander in Chief, Pacific Fleet, ca. 1942-1944 A Priceless Advantage: U.S. Navy Communications Intelligence and the Battles of Coral Sea, Midway, and the Aleutians Frederick D. Parker Center for Cryptologic History National Security Agency Reissued 2017 with a new introduction First edition published 1993.