The reader will feel the inspiration, freshness and enthusiasm of a new breakthrough in mathematical thought in the 4 seminal papers presented here for the first time ever in one volume. The 4 papers by Duistermaat, Guillemin and H rmander have been a milestone in the development of this field. The new ideas presented in these papers - in a very lucid and accessible form - became the foundation on which more and more abstract theories were built in...