The Atomic Force Microscope combines in a very unique way a very high sensitivity in detecting and applying forces (of up to a few 10's of piconewton), a high accuracy in positioning a sharp tip relativ to the sample in all three dimensions (of up to a few Angstrom), and the possibility to be operated under physiological conditions. This combination allows experiments not possible before, particularly in the field of biophysics and soft materials. One example is the mapping of mechanical properties with high spatial resolution of polymeric films and living cells. In living cells it is possible to probe the mechanics during dynamic processes like cell migration and cell division.