Professor Lehrer is distinguished for his many significant contributions to the complex representation theory of the finite groups of Lie type. A mathematician of unusually broad outlook and wide knowledge, he has become increasingly interested in the links with such subjects as geometry and topology. His achievements include the parametrization of the characters of the finite special linear groups, a comprehensive theory with R B Howlett of the decomposition of characters induced from parabolic subgroups and the recent determination of the action of a complex reflection group on the cohomology of the complement of its reflecting hyperplanes.