Geometry of Manifolds with Non negative Sectional Curvature : Editors: Rafael Herrera Luis Hernández Lamoneda Riemannian manifolds with positive sectional curvature An introduction to isometric group actions A note on maximal symmetry rank quasipositive curvature and low dimensional manifolds Lectures on n Sasakian manifolds On the Hopf conjecture with symmetry An Introduction to Exterior Differential Systems Providing an up to date overview of the geometry of manifolds with non negative sectional curvature this volume gives a detailed account of the most recent research in the area. The lectures cover a wide range of topics such as general isometric group actions circle actions on positively curved four manifolds cohomogeneity one actions on Alexandrov spaces isometric torus actions on Riemannian manifolds of maximal symmetry rank n Sasakian manifolds isoparametric hypersurfaces in spheres contact CR and CR submanifolds Riemannian submersions and the Hopf conjecture with symmetry. Also included is an introduction to the theory of exterior differential systems