The two organs of the body most accessible to examination are the eye and the skin and its appendages. That is why, it is said, ophthalmological genetics is in such flourishing good health. Dermatological genetics does not seem to have benefited so much from the skin being on the outside, and there are but few dermatological counterparts to the volumes of Sorsby, Waardenburg, Franceschetti and Franr,;ois, among others. But thanks to the growing interest in medical genetics, and the modern sophisticated tech­ niques of molecular, biochemical, and ultrastructural examination, der­ matology is beginning to catch up, as the appearance of this volume testifies. Because of the