Wilfred Stein is the author of three previous books on membrane transport, the first appearing almost fifty years ago. He has edited numerous books and written some 180 papers on various aspects of membrane transport and especially transport kinetics. These papers, especially those written together with his colleague William Lieb, defined many of the concepts used today in discussing movement across cell membranes. More recently he has turned to the study of the kinetics of drugs used in cancer therapy and in the treatment of malaria. He has taught biochemistry, biophysics and physiology at the University of Manchester and the Hebrew University of Jerusalem and also at the Weizmann Institute in Israel. He is currently Emeritus Professor of Biophysics at the Hebrew University. He is married to a librarian and has four children and nine grandchildren.