Another quick trip down memory lane, courtesy of the BBC's full cast audio adaptation of this novel starring Ian Carmiachel (who also starred in the first of the Beeb's two TV series based on Sayers's novels).
This was Sayers's revenge on the advertising business, based on her own early job experience as an advertising copywriter -- as well as (so her biographers tell us) her revenge on an ex-colleague who tried to blackmail her and who is made to tumble down an iron staircase modelled on the one at their former workplace, ending up dead. -- This is also the one Wimsey book (perhaps with the exception of the very first one, Whose Body?) where Wimsey is, at times, most similar to Bertie Wooster ... except that he's playing a role here, as he has been smuggled into Pym's Publicity for purposes of an undercover investigation into the tumbled-down man's death. What ensues is one of Sayers's wildest rides; a veritable harlequinade that has Wimsey even impersonating himself (or his evil look-alike cousin).
I would have preferred to obtain a reading of Sayers's actual book by Ian Carmichael (he was a brilliant narrator and had played Wimsey so often by the time these audio recordings came around that he had the character down pat and could slip him on and off like a well-worn sweater), but since for this particular book that doesn't seem to be available, I'll happily content myself with this full cast recording.