When A Don at War was published in 1966 it was hailed as the first book to be written from the point of view of the Intelligence staff officer in the field with critics remarking on Sir David Hunt's authoritative exposition of British as well as German strategies. Eight years later it was revealed that the British, through the Ultra' system, were able to decode even the most important German radio messages despite the fact they were sent in the supposedly unbreakable Enigma cipher'. Since 1974 the great secret has become common knowledge. As a result Sir David has specially written for this second edition a new foreword whose main purpose is to explain the use made of Ultra during four years campaigning in the Mediterranean.