The Miskatonic University Library Association (M.U.L.A.) Monographs are supplements for the Call of Cthulhu roleplaying game, usually covering unusual or esoteric subjects.
From the Chaosium description:
"Monographs are longer works by one or more authors on a subject of import to Chaosium 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, and evaluate the potential of these works for eventual release to the wholesale market. More importantly, they’re a lot of fun."