The Salem Horror by Henry Kuttner

The spirit of dark priestess Abigail Prinn, executed during the Salem Witch Trials, is awakened when a man moves into her old home and uncovers her secret "Witch Room" hidden beneath. In order to wreak her vengeance on the descendants of the townsfolk responsible for her death, Abigail attempts to summon forth a dark evil in the form of the Great Old One known as Nyogtha, using the Witch Room, but is ultimately thwarted by the intervention of occultist Michael Leigh. Check out this link to buy DB's Books[link]