As one reflects on the field of cutaneous photobiology, there have been so many outstanding basic science and clinical developments during the past decades that it is difficult to select those which are most important. However, a common theme underlying these developments has been a progression from morphologic and qualitative studies of photodermatoses to a quantitative and etiologically oriented analyses of photopathology. Being permitted a spirit of free inquiry, research in photobiology has found direct application to photosensitivity diseases. In addition to a better understanding of pathogenesis, photobiologic research has provided knowledge that has eventuated in the effective treatment and control of several photodermatoses. If I may exercise the prerogative of arbitrary choice, the following reflections are restricted to five photobiologic categories, with apologies for obvious omissions necessitated by limitations of space. They include: the porphyrias; drug photosensitivity; xeroderma pigmentosum; photochemotherapy; and future frontiers.
PORPHYRIAS
The "porphyrias" now refer to