During the past few years there has sprung up an abundant literature devoted to the subject of dermatomyositis. Despite this, it is commonly believed that this condition is extremely rare. Early in the course of my studies on lupus erythematosus1it became apparent to me that there were resemblances between that disease and dermatomyositis. The belief that this was so was based on observations made in cases showing certain similarities in eruption, clinical course, general outcome and especially the occurrence of what seemed to be "transitional" conditions. Contrariwise, there were also encountered many features that appeared to provide fundamental points of distinction, particularly if one considered only typical examples of each disease. In following the courses in such cases it was not uncommon to find that the nature of the clinical picture was often variously interpreted by the dermatologist, internist, pediatrician, neurologist and even the orthopedist. This is also