Genetic information determines the composition of molecules comprising cytoskeletal elements, membranes and receptors. The supramolecular arrangement of these components represents a self-assembly process controlled by physicochemical and mechanical interactions. This general hypothesis demarcates the aim of studying cellular mechanics. Description and evaluation of mechanical properties of cells and their organelles, as well as of the forces exerted by them, is the scope of this book on Cytomechanics. Emphasis is laid on the role of mechanical properties in the generation of shape and cytoplasmic motion, and on the basic principles and components determining mechanical properties.