When Captain Ridleys shooting party A arrived at Bletchley Park in 1939 no-one would have guessed that by 1945 the guests would number nearly 10 000 & that collectively they would have contributed decisively to the Allied war effort. Their role? To decode the Enigma cypher used by the Germans for high-level communications. It is an astonishing story. A melting pot of Oxbridge dons maverick oddballs & more regular citizens worked night & day at Station X as Bletchley Park was known to derive intelligence information from German coded messages. Bear in mind that an Enigma machine had a possible 159 million million million different settings & the magnitude of the challenge becomes apparent. That they succeeded despite military scepticism supplying information that led to the sinking of the Bismarck Montgomerys victory in North Africa & the D-Day landings is testament to an indomitable spirit that wrenched British intelligence into the modern age as the Second World War segued into the Cold War. Michael Smith constructs his absorbing narrative around the reminiscences of those who worked & played at Bletchley Park & their stories add a very human colour to their cerebral activity. The code breakers of Station X did not win the war but they undoubtedly shortened it & the lives saved on both sides stand as their greatest achievement."