Here you go: http://en.wikipedia.org/wiki/Cryptanalysis_of_the_Enigma#Pol...

The 20 years between the wars were an amazing time in Poland. It was perhaps the best time in Polish history of mathematics, with remarkable contributions from Stefan Banach and his other Lvov friends: http://en.wikipedia.org/wiki/Stefan_Banach http://en.wikipedia.org/wiki/Lw%C3%B3w_School_of_Mathematics

German military texts enciphered on the Enigma machine were first broken by the Polish Cipher Bureau, beginning in December 1932. This success was a result of efforts by three Polish cryptologists, Marian Rejewski, Jerzy Różycki and Henryk Zygalski, working for Polish military intelligence

http://en.wikipedia.org/wiki/Enigma_machine

Read any book on the history in question - it's no secret that the Poles were responsible for working out the details of the Enigma machines and how to break them. The British took their work and developed it into methods that were more general & powerful. Wikipedia is a good as place to start as any - follow the references: http://en.wikipedia.org/wiki/Cryptanalysis_of_the_Enigma.