Abraham Sinkov, one of the legendary cryptanalysts of WWII, died January 19 in Mesa, Arizona. He was one of the four original "codebreakers" of Friedman's US Army Signal's Intelligence Service in the 1930s. He was intstrumentally involved in breaking many of the Japanese codes during WWII and went to Bletchley Park in England to exchange US expertise on the Japanese PURPLE Code for British expertise on the German Enigma. He served at high levels of the NSA until his retirement in 1963, after which he taught mathematics at Arizona State University. He was author of the classic Elementary Cryptanalysis, which is still in print more than thirty years after its publication.