In Part One, Peshkin introduces the Aharonov-Bohm effect under the assumptions of standard quantum theory. The emphasis here is on the fundamental questions which are addressed directly by the experimental results and on other elementary aspects of the the theory that appear especially clearly in the present context. In Part Two, Tonomura gives a brief review of the diverse ideas that have been put forward during the protracted debate about the reality and meaning of the Aharonov-Bohm effect, followed by a detailed account of the experiments which finally settled most of those questions. The review is intended to give a flavor of the controversy rather than to do justice to every point of view.