Membranes composed of amphiphilic molecules are highly flexible surfaces that determine the architecture of biological systems and provide a basic structural element for complex fluids such as microemulsions. Recently, a variety of new experimental methods such as X-ray scattering, neutron scattering, and atomic force microscopy have been used in order to study themolecular structure of these membranes. Their conformational behavior, on the other hand, is studied by optical and electron microscopy, which reveals that membranes in aqueous solution exhibit an amazing variety of different...