Harold Liberty read Classics at Peterhouse, Cambridge before a career in teaching. As a chess player, musician and crossword addict, had he been born some decades earlier there is every chance he could have been a code-breaker. Certainly, he has been fascinated in the history of Bletchley Park since its work became public knowledge in the late 1970s and he took up stewarding and guiding there on retirement. His experience and knowledge led to the writing of this book.