From the Chaosium web site:
Another collection of twenty-five (possibly) spook-filled American House plans from the 18th, 19th, and early 20th centuries for use in Call of Cthulhu and Basic Roleplaying, and other history-based roleplaying games. Includes Colonial Era Houses (1640-1770), New Republic Era Houses (1770-1850), Victorian Houses (1850-1900), Early 20th Century (1900-1930), and offers notes on how to haunt a house.
MISKATONIC UNIVERSITY LIBRARY ASSOCIATION monographs are longer works by one or more authors on a subject of import to Call of Cthulhu roleplayers. On these products the author has also fulfilled the functions of editor and layout artist; we at Chaosium have done little in the way of editorial. We found these works compelling and thought that you would enjoy them. Through the publication of monographs we can offer our most loyal fans more information more easily, and evaluate the potential of these works for eventual release to the wholesale market.