Operating under the cover of a Code and Cypher "School," Bletchley Park was in fact the center for British code-breaking in World War II. Despite a rather thin cover, the Germans never guessed what was going on at Bletchley Park. These operations remained top-secret for over thirty years, concealing the true reasons for many key Allied decisions. This account covers code-breaking operations and techniques, the role of mathematical genius Alan Turing, and the development of early computers as a by-product of cryptography.