Walter Gilman is a man from from Haverhill, Massachusetts. He came to the Miskatonic University to advance his research in non-Euclidean calculus and quantum physics.
He takes board in the reportedly haunted Witch-House, which in the 1600's held the witch Keziah Mason. He eventually encounters her.
She enters his dreams, attempting to convince him to sign his name into the Black Book of Azathoth. He refuses recalling the horrors which where written of him in the Necronomicon.
Gilman is responsible for the death of the seventeenth century witch Keziah Mason.
He was killed when Mason's demonic rat, Brown Jenkin, ate his heart.