On the French side quite a lot has been written on the subject. There is of course Schulmeister, famous in France because of the television series and written about ad nauseam. Then there is the cabinet noir and quite a bit on Napoleon's spies. A lot of it is myth and legend. You'll find that French archives have been extensively tampered with, with people extracting their files and removing all the incriminating material, so the published stuff is quite often not reliable at all. It is a difficult subject that requires in depth knowledge both of the archives and of the "canvas on which history was written". Idem dito for the Austrians, the spying did not end in 1815. I can't comment on the other nations.
It might not be a such an "intelligent" choice