This preliminary list of incipits grew out of a card-file which I made to help me in the preparation of The Seven Deadly Sins published in 1952. It has been much expanded as a result of study in various libraries abroad and of a systematic search of certain manuscript catalogues and books. It can provide, I think, the nucleus for a complete list of incipits of Latin works on the virtues and vices, although at present it is far from complete or free from errors. Guides of this sort, I know from experience, can be of immense help in the wilderness of medieval manuscripts and through the labyrinth of medieval bibliography. I have no illusions about its state of perfection, but, inasmuch as the final form of this type of work must depend on the labors of many, someone must offer his contribution as a first step.