TOP SECRET ULTRA: Breaking Luftwaffe Ciphers at Bletchley Park

In 1941, Calvocoressi was assigned to a section of Bletchley dealing with Luftwaffe Ultra intelligence. As deputy head and, from 1944, as head, he spent the rest of the war translating and interpreting decrypted Enigma signals. The codebreaking operations ended in 1946 and remained classified until the mid-1970s. 16 pages of photos.