Layered crystals, characterized by a quasi-two-dimensional character of certain physical properties, play an interesting role in surface science. First of all they provide excellent inert substrates for epitaxial deposition and physisorption studies. The surfaces of layered crystals, however, are interesting in their own right because they make a relevant class of low-dimensional phenomena accessible to surface probes. Change density waves, incommensurate structures, phonon anomalies and high Tc superconductivity are well known examples. This book collects a series of review articles written by outstanding specialists on the structural assessment and spectroscopy of layered structures with surface-sensitive probes such as scanning microscopy and helium atom scattering, the theoretical analysis of their electronic and vibrational surface states, and the investigation of physisorbed overlayers.