Ultramagic

The dramatic story of the famous cracking of the codes ULTRA and MAGIC during
the Second World War has been told before, but in Battle of Wits Stephen
Budiansky takes advantage of newly declassified American and British documents,
and provides excellent diagrams to explain the process. As well as explaining
the primitive computers invented for decoding, he adds the story of another code
Venona and the US cracking of Soviet codes in the 1940s. Published by The Free
Press, £27.50, ISBN 0684859327