This book contains a collection of papers on the molecular biology of the band 3 proteins and their various functions: as anion transporters, binding proteins for membrane skeleton, hemoglobin and glycolytic enzymes, and as a recognition signal for the removal of senescent cells by the immuno-system of the body. The papers presented were written to provide an overview of the work carried out during the past five years in most of the laboratories engaged in research on band 3. They serve to give the reader factual information on nearly all aspects of band 3 research, to introduce him to the current literature and to give him a feeling for the philosophy behind the approaches chosen in the various laboratories.