The untimely death of JEnzY (GEORGE) 0LSZEWSKI on February 13th, 1964, represents a deep loss to neuropathology. JERZu 0LSZEWSKI was born on April 23rd, 1913, in Wilno. After his graduation from the medical faculty of Wi]no University in 1937 he became a research assistant of Prof. MAXI~ILIA~ ROSE, Director of the Brain Research Institute, Wilno University. The most formative years of his scientific career are connected with the Brain Research Institute of Prof. 0scA~ VOGT in Neustadt, Sehwarzwald, where 0LSZEWS~:I worked as a research associate between 1944--1948. Under the influence of 0. VOGT he mastered the difficult and assiduous art of cytoarchitectonic mapping of anatomical structures of the brain which later resulted in a series of unsurpassed cytoarchitectonic atlases of the reticular formation, brain stem and thalamus. These atlases became indispensable for anatomical correlations and are in constant use in various neurological laboratories throughout the world. In 1948 JERzu OLSZEWSKI came to the Montreal Neurological Institute at the invitation of Dr. W. G. ~)E~FIELD. In Montreal his main interest shifted from neuroanatomy to neuropathology and especially to the investigation of vascular permeability using radioactive iodinated albumin as the tracer. He published a number of valuable papers on this subject studying a variety of pathological conditions associated with increased vascular permeability in the brain. In 1956 he moved to the University of Saskatchewan, Saskatoon, where he developed an active department of neuropathology at the newly created medical school. Once this challenge was satisfied he left in 1959 for Toronto receiving a chair of neuropathology at the Banting Institute, University of Toronto. His interests in neuropathology covered a great number of topics. He was conscious that some of these problems could be elucidated profitably by modern research methods and he untiringly developed substantial facilities for research in his department. He was devoted in a monastic way to his work and to science and provided inspiration to his many students. For his kindness and warmheartedness he was loved by his friends and associates.