But it was not only the great minds and technological developments, which made the code breaking possible. First of all there was a big portion of luck, represented by the codebooks or Enigma machines that the Allies found or captured. Secondly there was the laziness of the German Enigma operators, which helped the code breakers a lot. Finally, this is not just the story of the people at Bletchley Park. Also the other players are not only worth mentioning, in fact their work was essential spadework for the Ultra project, which would not have been that successful without the prior achievements of the Polish code breakers of Biuro Szyfrów.