Enigma Variations: A Review Article.

In this essay, which began as a Review Article of the book X, Y & Z: The Real Story of How Enigma was Broken by Dermot Turing, I discuss some of the background details of the Enigma Cypher Machine. The machine was supposed to be 'unbreakable', as claimed (in particular) by the manufacturers. It was repeatedly broken by Polish and British mathematicians, employed in their respective countries' (and France's) bureaus; in particular, heroically, by Alan Turing (at Bletchley Park, UK) and Marian Rejewski (in Poznań, Warsaw and France) — but others played important parts, too. [ABSTRACT FROM AUTHOR]