4. 50 from Paddington

Agatha Christie's 1957 Miss Marple mystery opens with one of the genre's cleverest premises: a witness sees a woman strangled on a passing train, but no body is ever found. Miss Marple deduces where it must be and dispatches the efficient, charming Lucy Eyelesbarrow undercover to investigate the Crackenthorpe household — a family of squabbling adult children circling an inheritance. Lucy is one of Christie's most appealing creations, and the misdirection is vintage Christie at her most playful. The honest caveat: Miss Marple herself is largely offstage for much of the novel, and the large Crackenthorpe cast can be hard to track. The resolution arrives in a final-chapter rush. Still, this is among the warmest and most inventive of the Marple novels — clean, fun, and fully family-friendly.