The Tenth International Conference on Intracellular Protein Catabolism was held in Tokyo Japan, October 30-November 3, 1994. under the auspices of the International Committee on Proteolysis (lCOP). ICOP meetings have been held biennially in the USA, Europe, and Japan in turn. The previous three ICOP meetings (7th to 9th) were held in Shimoda, Japan, in 1988. in WildbadKreuth, Germany, in 1990, and in Williamsburg. Virginia, in 1992. Previous meetings were held in resort areas, this was the first meeting held in a large city. Attendance has grown every year so that nearly 400 participants from 19 different countries attended the Tokyo meeting. At the meeting, novel and updated results on the structure-function. physiology, biology, and pathology of proteases and inhibitors were discussed, together with cellular aspects of proteolysis and protein turnover. Thirty-nine invited papers and eight selected posters were presented orally and 171 poster presentations were discussed. This book documents almost all of the lectures and some selected posters. Since the world of proteolysis and protein turnover is expanding very rapidly. far beyond our expectations, it is impossible to cover all the new aspects of this field. However, this book will give an idea of the current status, trends. and directions of the field, and information necessary to understand what is and will be important in this field. Further. the editors hope that the novel ideas, approaches. methodologies, and important findings described in this book will stimulate further study on proteolysis and protein turnover.