Career
Hennan authored various articles and books on specific aspects of philately. These include:
Haiti: Postal History and Stamps (a series published over a 3-year period)
Curaçao Specialized (book published in 1952)
Doctor Hennan had various collections from which he authored philatelic articles Today he is remembered for his:
Chicago Postal History Collection
Doctor Hennan provided leadership in the philatelic field in various ways:
President of the American Philatelic Congress
President of the American Philatelic Society
President of the Collectors Club of Chicago
Various positions in the Chicago Philatelic Society (Honorary Life Member).
