X‐ray Photoelectron Spectroscopy(XPS) and Auger Electron Spectroscopy(AES) are two of the most powerful materials analysis techniques available today. First, the fundamental concepts underlying these methods are presented in simplified form. Then the most important problem areas of concern to workers in these fields are examined. These are: radiation damage, the technology of ion milling, and quantitative analysis. The complexity of these areas is illustrated from what is already known, and some problems that arise in areas that are still incompletely understood are discussed. Finally, the relative merits of XPS and AES are considered by evaluating the performance of each technique with respect to: (1) sensitivity, (2) speed, (3) spatial resolution, (4) depth resolution, (5) chemical bonding information, (6) sample damage, (7) quantitative analysis, and (8) electrostatic charging problems. Scores have been assigned for each of these 8 criteria for XPS and AES; at present, AES is found to have a significantly higher total score. These criteria have also been evaluated assuming that all the theoretical limits can be attained. In that limit, some problems are expected to remain for AES with respect to sensitivity, chemical bonding information, damage, and charging; however, with XPS, all of the performance criteria become superior to AES except for spatial resolution. The total performance score for XPS then becomes much higher than for AES.