Abstract Reflection anisotropy spectroscopy (RAS) is a non‐destructive optical probe of surfaces capable of operation within a wide range of environments. The RAS technique was developed to study semiconductor growth and more recently has been used to probe the optical properties of metal surfaces. Surface sensitivity has been demonstrated with the detection of reconstruction, adsorbate interaction and the observation of transitions involving surface‐localized electronic states. The RAS technique has non‐ultrahigh vacuum (UHV) environment capability and thus opens up the study of metal surfaces in catalytic and corrosive environments at high pressure and at the solid/liquid interface. The combination of RAS with a full range of surface science techniques applied to the study of well‐defined surfaces aids in the interpretation of RAS spectra. The focus of this article will be on well‐characterized metal surfaces prepared and studied under UHV conditions. Copyright © 2001 John Wiley & Sons, Ltd.