The world of American cryptology was still tiny. There were only three codebreaking units in government, with fewer than fifty employees among them. The largest and best-funded unit, with two dozen people, was run by the former army lieutenant Herbert Yardley. After the war he had won funding from the State Department to launch a codebreaking bureau in New York City, in a four-story town house off Lexington Avenue. He considered it a modern version of
