Lee A. Segel (1932-2005) was a Professor at the Weizmann Institute of Science, Rehovot, Israel, where he served as Chairman of Applied Mathematics, Dean of Mathematical Sciences and Chairman of the Scientific Council. He was an Ulam Scholar at the Los Alamos National Laboratory, a Fellow of the American Association for the Advancement of Science and a member of the Santa Fe Institute, where he continued his work on complex adaptive systems. He served as editor or editorial board member of six journals.