May Sinclair was the nom de plume of Mary Amelia St. Clair (1863-1946), a British writer who wrote novels, short stories and poetry. She was an active suffragette and a spiritualist.

'The Nature of the Evidence' is a ghost story about a first wife who returns to this world when her husband remarries, to protest her disapproval of his choice of second wife and prevent the two of them from ever sharing a bed.