Louis P. Pertschuk, D. O., is Associate Professor of Pathology at State University of New York. Downstate Medical Center, and Attending Pathologist at the Kings County Hospital Center. Brooklyn. New York. Dr. Pertschuk received an A.B. in Biology from New York University in 1946 and graduated from the Philadelphia College of Osteopathic Medicine in 1950. Following a year of internship he entered private general practice until 1970 when he began a residency in pathology at the State University-Kings County Hospital Center. He was a Fellow in Pathology at the Memorial Sloan-Kettering Cancer Center in 1973 and 1974 and was certified in Anatomic Pathology by the American Board of Pathology in 1974. Dr. Pertschuk is a Fellow of the College of American Pathologists and the American Society of Clinical Pathology. He is a member of the American Association of Pathologists, the International Academy of Pathology, the New York Academy of Sciences, and the merican Association for the Advancement of Science. He has published 67 research papers, 43 scientific abstracts, and contributed 19 chapters to various books. His current research interests include the development and study of different methodologies for detection of the sites of action of steroid hormones, especially in human neoplasia.