She Who Was No More is a psychological suspense novel by the writing team of Boileau-Narcejac, originally published in French as Celle qui n'était plus in 1952.

His mistress, physician Lucienne, desires to open a practice in Antibes, so she and Fernand conspire to murder his spouse to collect on her life insurance policy of two million francs.

They drown her in a bathtub, then make the death look like an accident, but things spiral out of control when her body disappears.

Rose Feld wrote in the New York Herald Tribune that the finale constitutes "an astounding turn that holds validity both for plot and characterization.

"[14] The editors of World Authors, 1950-1970 wrote: "The reader is so thoroughly drawn into the tale, so teased with faint subliminal hints and doubts, that the shatteringly unexpected conclusion is immediately and terrifyingly believable, in terms of both plot and character.