David R. Morrison

Made many recognized contributions in pure algebraic geometry, but is all but unique in the role he played in applying methods of algebraic geometry to mathematical physics -- especially to problems of quantum fields and strings. Many mathematicians have become interested in these problems, but he stands out for going into the physics deeply enough to really be able to contribute to the development of the physics and made many important contributions involving topology change, black holes, phase transitions, localization of path integrals, and too many topics to properly summarize in 100 words.