by - Harper, Stephen
How HMS Petard Seized the German Naval Codes
2000, Sutton Publishing, Limited
Hardcover, 128 pages
From the publisher: "An attack by a British destroyer on a German U-boat in the Eastern Mediterranean in October 1942 altered the course of the entire war. The capture of secret German Enigma coding material from U-559, at the cost of the lives of two of HMS Petard's crew, enabled Bletchley Park's codebreakers to successfully crack the U-boat cypher."
First published in the UK in 1999.