Book on French AF 1939-40?

The whole "ULTRA" deciphering activity in Britain, which provided the Allies with incredibly important and useful intelligence, started in Poland thanks to the Polish secret service (I presume) and in particular a young Polish mathematician who was a genius and a member of the team. They had performed all the fundamental and the most important work already when Poland was invaded. They passed the whole thing to the French, who continued the work already 1939 with the help of some Polish experts and kept the British entirely informed, with some British officers taking part in the ongoing work. Numerous German messages were decrypted already albeit they were only a small fraction of the whole coded radio traffic. They probably decrypted some decisive messages on operation "Paula" but I understand at least the French had a well-placed German agent in Luftwaffe headquarters, too (Schmidt; I think he was a relative of LW general Schmidt). Britain certainly had some good agents in Germany too.

When France was invaded too obviously the whole Enigma-business was passed on to the British, who further refined and developed it, hence Bletcheley Park etc.

There is no doubt that all this remarkable activity was started by Polish experts.

You see, it is fully possible to discuss Poland and France at the same time without wholesale insulting a whole country or a whole air force. That's a relief!