Best-kept secret: Canadian secret intelligence in the Second World War

The title is somewhat misleading. This is an account of the Canadian SIGINT effort during WWII with a postwar chapter to bring it up to date.Although one thinks of Canada as the empty "Great White North" there is a band of population in the provinces just north of the Border which in the Lakes area is actually south of Boston and New York. In this area are many prominent universities and research centers. It was in such that the beginnings of independent Canadian efforts began. Even the notorious Herbert Yardley was involved until the US authorities told the Canadians to get rid of him or there would be no cooperation. Yardley was the erstwhile the chief of the US black chamber (code breakers) in WWI and after and when he was let go, he wrote a tell all book which resulted in the Japanese changing all their codes and ciphers in the 1930s.The author is a well known researcher concerned with the Canadian scientific war efforts. He has thoroughly mined the relevent archives of the nations involved to tell the story of these efforts and cooperation with the US and Great Britain. Much on the interservice wrangling in the US and not very much on use of the information nor is there much on the mechanics of SIGINT and code breaking. This is an organizational history and deserves a place on the shelf of the specialist. Not for the casual general reader.