Which Lovecraft story features a student named Walter Gilman?

The Lovecraft story featuring student Walter Gilman is “The Dreams in the Witch House.”

Gilman is a mathematics and folklore student at Miskatonic University who rents an attic room in Arkham’s notorious Witch House. The room’s strange angles lead him to investigate non-Euclidean geometry, higher dimensions, and the possibility that space can connect otherwise distant worlds.

The story was written in January and February 1932 and first published in Weird Tales in July 1933. Gilman’s academic interests become entangled with the occult history of Keziah Mason, an accused witch who escaped from a Salem jail in 1692. His dreams bring him into contact with Mason, Brown Jenkin, and Nyarlathotep.

Readers sometimes confuse the title with Lovecraft’s other Arkham stories, especially “The Unnamable” or “The Silver Key.” Those tales share settings and themes, but Walter Gilman is specifically the protagonist of “The Dreams in the Witch House.”