Hello! I'm looking for some great 'puzzle mysteries': that is, detective novels where the primary focus is on the whodunnit aspect, as opposed to a broader plot, deep characterization, etc. I like putting the book down periodically to work out my own theories (ex: suppose the killer were Mr. Smith...and he slipped out of the party an hour before he claimed he did, and then...but wait...that would mean...of course! etc.) The Mysterious Affair at Styles (Agatha Christie) was just about right (the specific layout of the house, the manageable list of suspects). The Nine Tailors (Dorothy Sayers) was excellent, and featured some puzzle-like aspects, but had decidedly larger themes and longer digressions. Then there was The Big Sleep (Raymond Chandler). Again, I enjoyed the novel, but there was hardly any puzzle at all. To me, it was more like an action film than a detective story, with constant activity but very little in the way of logic to work out. What would you recommend? I've heard The Five Red Herrings (Sayers) fits the bill. What else?