The best way to find out if you have any friends is to go broke. The ones that hang on longest are your friends. I don't mean the ones that hang on forever. There aren't any of those.

At least half the mystery novels published violate the law that the solution, once revealed, must seem to be inevitable.

If you liked a book, don't meet the author

Writers who get written about become self-conscious. They develop a regrettable habit of looking at themselves through the eyes of other people. They are no longer alone, they have an investment in critical praise, and they think they must protect it. This leads to a diffusion of effort. The writer watches himself as he works. He grows more subtle and he pays for it by loss of organic dash.

Love interest nearly always weakens a mystery because it introduces a type of suspense that is antagonistic to the detective's struggle to solve a problem.

Love interest nearly always weakens a mystery because it introduces a type of suspense that is antagonistic to the detective's struggle to solve the problem. It stacks the cards, and in nine cases out of ten, it eliminates at least two useful suspects. The only effective love interest is that which creates a personal hazard for the detective - but which, at the same time, you instinctively feel to be a mere episode. A really good detective never gets married.

The dilemma of the critic has always been that if he knows enough to speak with authority, he knows too much to speak with detachment.