Part I In the last twenty-five years, a great many instructive papers have been written on the various types of cancer of the skin. The majority of these contributions, however, have been made by specialists in some field of therapeutics, and consequently carry a certain amount of bias for a method of treatment. The controversies over the pathologic aspect of skin malignancies which enriched the literature at the beginning of the century have subsided, and that phase of the question appears to be settled. Hazen, in his "Skin Cancer," has presented the subject admirably, and has given us a reference book for the advanced student. No one else, so far as I know, has attempted to concentrate our knowledge simply and with an unprejudiced point of view, so that the medical student and practitioner, may have a brief resume available. It seems worth while, then, to consider briefly some of