May Sinclair was the pseudonym of Mary Amelia St. Clair (24 August 1863 – 14 November 1946), a popular British writer who wrote about two dozen novels, short stories and poetry.

[2] Sinclair was also a significant critic in the area of modernist poetry and prose, and she is attributed with first using the term 'stream of consciousness' in a literary context, when reviewing the first volumes of Dorothy Richardson's novel sequence Pilgrimage (1915–1967), in The Egoist, April 1918.

Here she de-bunked theories put forward by Sir Almroth Wright that the suffragists were powered by their sexual frustration because of the shortage of men.

[5] In 1914, she volunteered to join the Munro Ambulance Corps, a charitable organization (which included Lady Dorothie Feilding, Elsie Knocker and Mairi Chisholm) that aided wounded Belgian soldiers on the Western Front in Flanders.

She wrote early criticism on Imagism and the poet H. D. (1915 in The Egoist); she was on social terms with H. D. (Hilda Doolittle), Richard Aldington and Ezra Pound at the time.

Some aspects of Sinclair's subsequent novels have been traced as influenced by modernist techniques, particularly in the autobiographical Mary Olivier: A Life (1919).

[8] Brian Stableford has stated that Sinclair's "supernatural tales are written with uncommon delicacy and precision, and they are among the most effective examples of their fugitive kind".