This work is designed as a reference tool for researchers investigating the what, when, and why of the Japanese attack on Pearl Harbor in 1941. The book provides, for the first time, a cross-referencing and indexing of the total record of testimony and evidence that was compiled and published by the U.S. Congress following U.S. investigations into the Pearl Harbor attack. Transcripts from the postwar hearings contain significant information about the diplomatic background of the hostilities, the first look at the crypto-analytic activities of the U.S. military, and many of the communications between Washington D.C. and Pearl Harbor. Eyewitness accounts of the Japanese attack and information on the United States response to the attack are also found in these records. The many hundreds of citations for such persons as President Roosevelt, Cordell Hull, and Admiral Stark are generated from nearly 30,000 pages of testimony and evidential material, and have been assembled into main and subcategories to aid the researcher. The citations involving President Roosevelt, for example, are made up of over 50 subcategories. This work cites all persons connected to the Pearl Harbor attack, all ships involved, and it contains many letters, memoranda, messages, and dispatches which are listed chronologically. To distinguish ship names from people, warships from merchant ships, and people from places, the Index uses the various type fonts that appeared in Samuel Eliot Morison's Vol. 15 (General Index) of The History of United States Naval Operations in World War II. This volume is suitable for Government Deposit libraries, college and research libraries, public libraries, and federal government offices.