Abstract
The occurrence of localized magnetic moments in dilute alloys is a consequence of strong electron-electron correlation effects in the case of localized electronic states. The importance of this topic derives, at least in part, from its close relationship to the complicated problem of bulk magnetism in metals. Unfortunately, despite its intuitively simpler structure, the magnetic impurity problem continues to defy a satisfactory solution. Traditionally, the problem has been divided into two distinct parts. The first deals with the conditions under which a local moment can form; the second is concerned with the properties of the moment.