Three full-length novels from Clement (Still River, 1987) dating from an era when novels ran to 150—200 pages and didn’t wear out their welcome. Most of his best works feature children and young people solving intriguing puzzles within a solid science framework. In Needle (1949), an alien criminal crash-lands on Earth, closely pursued by a policeman of the same species. The twist is that they’re parasitic blobs of jelly, dependent on a host to survive. Iceworld (1953) lacks both a puzzle and youthful protagonists; an alien criminal from a very hot, bright planet perceives Earth as a gloomy, frigid netherworld. The brave young girl and her alien counterpart of Close to Critical (1958) become trapped on the surface of a planet under conditions where phase changes make water unpredictable. Persuasive aliens, remarkable world-building, and splendid puzzles: fans partial to any of these will find Clement well worth investigating.