This recent government publication investigates an area often overlooked by historians: the impact of the Holocaust on the Western powers' intelligence-gathering community. A guide for researchers rather than a narrative study, it explains the archival organization of wartime records accumulated by the U.S. Army's Signal Intelligence Service and Britain's Government Code and Cypher School. In addition, it summarizes Holocaust-related information intercepted during the war years and deals at length with the fascinating question of how information about the Holocaust first reached the West. The guide begins with brief summaries of the history of anti-Semitism in the West and early Nazi policies in Germany. An overview of the Allies' system of gathering communications intelligence follows, along with a list of American and British sources of cryptologic records. A concise review of communications intelligence notes items of particular relevance to the Holocaust's historical narrative, and the book concludes with observations on cryptology and the Holocaust. Numerous photographs illuminate the text.