Cornerstone: The Moving Toyshop by Edmund Crispin.
Note: This continues my occasional series on the Haycraft-Queen Cornerstone list (those mysteries deemed essential by Howard Haycraft and Ellery Queen).
Edmund Crispin's Gervase Fen series has a delightful screwball quality to it, as evidenced in Crispin's Love Lies Bleeding: "... the boys sang [the school song] with the exuberance of reprieved assassins."
In The Moving Toyshop (1946), Oxford professor Fen (who sounds remarkably like the White Rabbit from Alice in Wonderland) seeks to resolve the mystery of a murder victim found in a toyshop, which is replaced by a grocery store the next day, with no sign that a corpse ever existed. A notable and hilarious sequence is when a cohort of Fen's enlists a group of inebriated Oxford undergraduates as muscle merely on the promise of a drink.
Crispin is the pseudonym of composer Robert Bruce Montgomery (1921-78), who worked on scores for six "Carry On" films and some of the "Doctor in the House" series; he also edited some science fiction collections. There's a new biography, Bruce Montgomery/Edmund Crispin: A Life in Music and Books by David Whittle, out from Ashgate.
Maggie Topkis's Felony & Mayhem Press has reprinted several titles in the Fen series: The Case of the Gilded Fly, Swan Song, and Holy Disorders, and will be reprinting Love Lies Bleeding (also an entry on the Haycraft-Queen list) later this fall.