http://www.imdb.com/title/tt0078488/?ref_=fn_al_tt_1Dreadful but good, if you see what I mean!
Found this one years ago in some second hand store and bought it for fun. I truly enjoyed it even though (as someone else noted) the mystery part wasn't very suspenseful. But the characters are fun and the story zips along at a fast pace. The movie version (with George Segal) wasn't that bad an adap...