Developments in surface science have provided atomic-scale surface images and helped us to understand surface reactions at an atomic-scale Two big gaps the pressure gap and material gap were believed to exist between real catalyst systems and surface science targets however they are now being filled Nonlinear optical phenomenon of sum-frequency generation glancing-angle X-ray and scanning probe techniques have been developed as ambient pressure surface analysis methods Great efforts have made it possible to perform X-ray photoelectron spectroscopy measurements in the presence of gas-phase reactants Recent improvements in surface analysis techniques for nonconducting targets enable us to investigate metal clusters on well-defined oxide surfaces to fill the material gap We are now able to initiate and control the surface reactions artificially by adjusting physical parameters Surface science has reached a new stage not only for determining the surface structures electronic properties and reaction mechanisms but also for synthesizing highly active surfaces and controlling catalytic reactions artificially (C) 2010 Elsevier BV All rights reserved