Books like The House on the Borderland

A manuscript is found: filled with small, precise writing and smelling of pit-water, it tells the story of an old recluse and his strange home - and its even stranger, jade-green double, seen by the recluse on an otherworldly plain where gigantic gods and monsters roam.Soon his more earthly home is no less terrible than his bizarre vision, as swine-like creatures boil from a cavern beneath the ground and besiege it. But a still greater horror will face the recluse - more inexorable, merciless and awful than any creature that can be fought or killed.A classic of the first water - H. P. Lovecraft