This book describes recent developments in optical techniques for extracting surface and interface information with a resolution of less than a single atomic layer. These new "epioptic" techniques have now been quite widely applied to semiconductor surfaces and interfaces, and include polarised reflection techniques such as reflection anisotropy spectroscopy and spectroscopic ellipsometry, Raman scattering, and optical second harmonic and sum frequency generation. Epioptics has great potential in the area of growth monitoring, and in situ monitoring of semiconductor growth with submonolayer...