Formation of Singularities in the Mean Curvature Flow.- Geometry of hypersurfaces.- Examples.- Local existence and formation of singularities.- Invariance properties.- Singular behaviour of convex surfaces.- Convexity estimates.- Rescaling near a singularity.- Huisken's monotonicity formula.- Cylindrical and gradient estimates.- Mean curvature flow with surgeries.- Geometric Flows, Isoperimetric Inequalities and Hyperbolic Geometry.- The classical isoperimetric inequality in Euclidean space.- Surfaces.- Higher dimensions.- Some applications to hyperbolic geometry.