The Mare's Nest is a 1964 book by David Irving, focusing on the German V-weapons campaign of 1944–45 and the Allied military and intelligence effort (Operation Crossbow) to counter it. The book covers both sides of the story – the Allied arguments over how to interpret intelligence concerning the V-weapons (or even whether they existed) and the German debate over how to deploy the new weapons to make the most of their supposed capacity to reverse the tide of the war. During his research for the book, Irving discovered that the Allies had broken the German Enigma code, over a decade before that became public knowledge, but agreed to keep it secret. The Mare's Nest was well received by reviewers and those involved in Operation Crossbow and has been widely cited by authors writing about the V