Alan S. Perelson is a Staff Member of the Theoretical Biophysics Group, and an affiliate of the Center for Nonlinear Studios, University of California, Los Alamos, National Laboratory, Los Alamos, New Mexico. He received his Ph.D. in Biophysics from the University of California, Berkeley, in 1972. Perelson received the N.I.H. Research Career Development Award (1979-1984); and the Bousch Lomb Medal for Excellence in Biology. His research interests are the application of mathematics to immunological, physiological, chemical, and biophysical problems.