Coordinating Editors

We are honored to pay tribute to Johannes (Hans) J. Duistermaat (December 20, 1942–March 19, 2010), a world leading figure in geometric analysis and one of the foremost Dutch mathematicians of the twentieth century, by presenting a collection of contributions by someofHans’s colleagues, collaborators, and students. Duistermaat’s first striking contribution was his article “Fourier integral operators II” with Hörmander (published in Acta Mathematica), a work that he did after his doctoral dissertation. Several influential results in analysis andgeometryhave the nameDuistermaat attached to them, for instance, the Duistermaat-Guillemin trace formula (1975), Duistermaat’s global actionangle theorem (1980), the Duistermaat-Heckman theorem (1982) and the Duistermaat-Grunbaum bispectral theorem (1986). Duistermaat’s papers offer an unusual display of originality and technical mastery. Hans Duistermaat passed away on March 19, 2010, in The Netherlands. Hans had been affiliated with the Mathematics Institute at Utrecht University as Professor of Pure and Applied Mathematics