Short answers, pulled from the story.
Bletchley Park was the principal centre of Allied code-breaking during the Second World War, housing the Government Code and Cypher School (GC&CS). The team there regularly broke the secret communications of the Axis powers, most importantly the German Enigma and Lorenz ciphers, and at its peak was reading approximately four thousand messages per day.
At the peak of operations in January 1945, 8,995 personnel worked at Bletchley Park and its outstations, about three-quarters of them women. Codebreakers included Alan Turing, Gordon Welchman, Mavis Lever, Margaret Rock, Hugh Alexander, Stuart Milner-Barry, Bill Tutte, and Joan Clarke, alongside linguists, chess champions, mathematicians, and crossword solvers.
Colossus was the world's first programmable digital electronic computer, designed and built by Tommy Flowers and his team at the Post Office Research Station at Dollis Hill to help break the German Lorenz cipher. The prototype was delivered to Bletchley Park in January 1944 and first operated on live traffic on the 5th of February 1944; Flowers then produced one Colossus per month for the rest of the war, reaching a total of ten machines.
Admiral Sir Hugh Sinclair purchased the Bletchley Park mansion and fifty-eight acres of land in May 1938 using six thousand pounds of his own money, after the British Government said it lacked the budget. He and his colleagues had inspected the site while posing as a shooting party under the cover name "Captain Ridley's shooting party."
Public discussion of Bletchley Park's work in the English-speaking world became accepted with the publication of F. W. Winterbotham's The Ultra Secret in 1974. The British government did not fully acknowledge the contribution of those who served there until July 2009, when a commemorative medal bearing the inscription GC&CS 1939-1945 Bletchley Park and its Outstations was struck.
Women made up about three-quarters of the nearly nine thousand personnel working at Bletchley Park and its outstations at the peak of operations. They worked as cryptanalysts, translators, and Colossus operators; Mavis Lever solved the signals revealing Italian naval plans before the Battle of Cape Matapan, and Margaret Rock co-solved the Abwehr cipher, while Jane Fawcett decrypted a vital message concerning the German battleship Bismarck.