On the 31st of March, 1999, Dr. Masakazu Matsui retired from Kyoto University after 38 years of service to the University and was honored with the title of Professor Emeritus of Kyoto University. Dr. Matsui was born in Hyogo on the 13th of July, 1935. After graduation from Faculty of Science, Kyoto University in 1959, he continued his studies on the synthesis and application of α-dioximes for metal analysis as a graduate student. In 1961, he was appointed an instructor of the Laboratory of Radiochemistry, Institute for Chemical Research, Kyoto University, under the supervision of the Emeritus Professor Tsunenobu Shigematsu. He was granted a doctoral degree from Kyoto University in 1966 for his studies on coprecipitation mechanism with calcium oxalate. On a leave of absence in the year 1969 to 1970, he worked on the ion-selective electrode in cooperation with Professor H. Freiser at Arizona University. In 1972, Dr. Matsui was promoted to Associate Professor at the Laboratory of Radiochemistry, Institute for Chemical Research, Kyoto University. In 1982, he was appointed full Professor of Kyoto University and directed the Laboratory of Radiochemistry (present name, Interface Science III), Institute for Chemical Research. At the Graduate School of Science, Kyoto University, he gave lectures on Radiochemistry, Analytical Chemistry and Geochemistry, and supervised the dissertation works of many graduate student. His sincere and warmhearted character has been admired by his friends, colleagues and students. Dr. Matsui devoted himself to the Japan Society for Analytical Chemistry, and officiated as Vice-President of the Society between 1994-1995. He was a member of the interdisciplinary committee of world cultural council, and the trustee of Japan Society of Solvent Extraction Chemistry and others. He has also chaired the International Symposium on New Sensors and Methods for Environmental Characterization. During the past 37 years, his research interest encompassed a wide array of radiochemistry, separation chemistry, inorganic chemistry, molecular recognition, environmental chemistry and geochemistry. His contribution to the Institute through both academic and administrative activities is hereby gratefully acknowledged, and his academic achievements are briefly described below. Dr. Matsui's work has been concerned with selective complex formation systems based on the concept of molecular recognition, and the separation chemistry in the selective metal chelate system employing the new ligands. He designed and synthesized a new series of ligands (host molecules), in particular, β-diketone, acylpyrazolone and polypyrazolylborate derivatives that have novel functions with improved stability and separability of metal ions and guest molecules. His research interest in molecular recognition was highlighted by the X-ray crystallography of metal chelate complexes. He extensively investigated various mechanisms of ion size discrimination derived from structures of the ligand and complexes, such as bite size, rigidity and interligand contact. As a geochemical aspect of his research, he established novel analytical methods for trace elements in the hydrosphere and studied their applications. He also elucidated circulation and biochemistry of minor and trace elements in the open ocean and Lake Biwa. Owing to his brilliant achievements, he was awarded a prize from Japan Society for Analytical Chemistry in 1995. Thus, Dr. Matsui has shown us an ideal direction of the academic research that the successful application can be attained only by a thorough understanding of the fundamental phenomena. This principle will remain as a firm basis underlying the research work in the Institute.