Ask a Policeman
by The Detection Club (Arthur Baker, 1933)
aka John Rhode, Helen de Guerry Simpson, Gladys Mitchell, Anthony Berkeley, Dorothy L. Sayers, and Milward Kennedy
audiobook read by David Timson (Lamplight, 2020)
A fix-up murder mystery where famous detective novelists swap protagonists and one-up themselves providing different investigations of/solutions to the same crime. Intended as a parody, supposedly, but all very self-indulgent and neither humorous nor engaging—more an increasingly turgid raking of minutiae.