Some comments on the history, theory, and applicationsof symplectic reduction -- Homology of complete symbols and non-commutative geometry -- Cohomology of the Mumford quotient -- Poisson sigma models and symplectic groupoids -- Pseudo-differential operators and deformation quantization -- Singularities and Poisson geometry of certainrepresentation spaces -- Quantized reduction as a tensor product -- Analysis of geometric operator on open manifolds: a groupoid approach -- Smooth structures on stratified spaces -- Singular projective varieties and quantization -- Poisson structure and quantization of Chern-Simons theory -- Combinatorial quantization of Euclidean gravityin three dimensions -- The Yang-Mills measure and symplectic structureover spaces of connections.