The Inner Room by Robert Aickman

Petite trade paperback.  Recommended.

In perhaps the most magnificent of what he called his "strange stories, Robert Aickman blurs the lines between memory, premonition and the hallucinated life.

Lene, a woman now recovering from the losses of the Second World War, recalls a gothic dolls' house of her childhood and the way in which its uncanny inhabitants entered her dreams. Most chillingly, the geometries of the house didn't add up; there had to be a secret room inside it. Years later, she comes across a life-size version in a wood not marked on any map . . .