This award will support the Workshop/Conference on Geometric Rigidity to be held May 15-20, 1989 at the University of Colorado, Boulder under the direction of Professors Steven Hurder and Arlan Ramsay. The conference will bring together researchers in the subfields of rigidity theory for geometric structures where the use of geometric techniques is emphasized and will focus on new areas of this subject. Rigidity theory has a long history and is one of the main themes in Riemannian geometry.