Agatha Christie

An obvious recommendation, but Christie is the "Queen of Crime" for a reason. Her puzzles are exceptionally clever, but what makes them compelling mysteries is her ability to capture character. Where contemporary mysteries often do this at book-length (and, I'd argue, so does her contemporary Dorothy Sayers), she's unusually good at sketching people with a few bold strokes and telling details. That doesn't just go for her detectives, but for every character who appears for more than a paragraph....