An Fe- and Cu-Protein Symposium was held on December 15-18, 1975 at the East West Center-University of Hawaii and was sponsored by the United States-Japan Cooperative Science Program under the auspices of the National Science Foundation and the Japan Society for the Promotion of Science. It was recognized by the organizers of the symposium that metalloproteins are very important in the field of health science and a subject worthy of discussion by experts from the United States, Japan and Europe. The meeting was restricted to Fe- and Cu-proteins but this is still a very broad subject matter and therefore, selected topics of current interest in this field were chosen. This book contains the collected papers from most of the symposium participants. The subject matter covered in this book is divided into four parts. These are: 1) the iron-sulfur proteins (which are not a part of the mitochondrial electron transport system); 2) the iron-sulfur proteins and heme proteins of the mitochondrial electron transport system; 3) other heme and nonheme iron proteins; and 5) selected copper proteins. The organizers of the symposium wish to express their gratitude to the participants, the session chairmen, and Drs. I.C. Gunsalus and E. Frieden who assisted in the organization of the symposium.