Owing to the increased availability of synchrotron sources, surface X-ray scattering is a rapidly expanding technique with important applications to surface structures and surface phase transitions, roughening of surfaces and interfaces, and the structure of liquid surfaces, including polymers, liquid crystals, and organic films. Surface studies with neutrons, on the other hand provide important information on liquid andmagnetic films. The contributions to this volume, written by active researchers in the field, provide an up-to-date overview of the highly sophisticated techniques and their applications.