Although the Vatican Film Library at Saint Louis University has been described recently in such diverse publications as the London Times, Osservatore Romano, Time, The American Historical Review, the Saturday Review and the National Geographic, it has never been explored fully by the scholarly world. The object of this article is to describe the extent of the microfilm collection at Saint Louis University, to provide some guides to the use of the manuscripts, and to indicate some possible areas of fruitful research in business and economic history.