Mystery at Lynden Sands is a 1928 detective novel by the British author Alfred Walter Stewart, published under his pseudonym J.J.

[1] It is the third in a series of novels featuring the Golden Age Detective Chief Constable Sir Clinton Driffield.

[2] It received a generally positive critical reception, with one reviewer going so far as to say it "may just fail of being the best detective story of the century" comparing it to The Cask and The Mysterious Affair at Styles.

[3] In A Catalogue of Crime by Jacques Barzun and Wendell Hertig Taylor describe it as "early but not first-class Connington".

Two subsequent murders on the beach of Lynden Sands itself require all Sir Clinton's skills as a puzzle-solving detective to piece together the various clues and sandy footprints collected between the rising and falling tides.