The Mystery of a Good Mystery

I've been reading a lot of detective novels of late, and by a lot, I mean two. First, there was THE SHERLOCKIAN by Graham Moore and lately I've been enjoying THE MANUAL OF DETECTION by Jebediah Berry. Normally, I wouldn't say I'm much of a mystery buff, but I've been enjoying these detective novels so much that I'm starting to really warm to the genre. And I think what makes both of these novels great, is their ability to keep the whodunnit completely unguessable right up to the bitter end.

It's a very rare and precious skill to able to craft a good mystery. I'd say ninety five percent of the time, when I sit down to read one, I already know who did it within the first chapter or two. But to be completely dumbfounded page after page, desperately trying to assemble the clues as you creep towards the end, that is something brilliant. And to be perfectly honest, I don't know how they do it. It's like a really good magic act. The slight of hand is so subtle you don't even realize it's happening.

What is the best mystery you've ever read? Of course, we have to give props to the Sherlock Holmes stories, those are undoubtedly the best. But, aside from such an obvious choice, which mystery left you so startled and amazed you never forgot it? What was it that made it so unforgettable? I'm not just asking rhetorical questions here either. I really want to know. Because when I finish my current detective novel, I want another one. So, help a fellow reader out!