The focus of this book is the elasticity of semiflexible polymers. The statistical physics of short semiflexible filaments has been studied in the context of single molecule stretching experiments. Such studies are relevant to the understanding of the elasticity properties of biopolymers like DNA, actin and microtubules. There is a chapter devoted to the study of membranes. Experiments on red blood cells (RBCs) trapped optically have been described and a simple theoretical model to account for the observed features has been proposed.