This monograph is intended to provide a critical review and analysis of recent studies of the electromagnetic structure of nucleons. The first chapter is devoted to a precise definition of what is meant by the electromagnetic form factors. The different types of experiments which have given information on these form factors are discussed in Chapter II with emphasis on the theoretical assumptions and approximations made in analysing the experimental numbers in terms of form factors. Chapter III is devoted to the recent dispersion theoretic analyses of the form factors. The theoretical development here has the two goals of serving as a first introduction to the dispersion methods for physicists at the graduate level and of indicating clearly the various approxima tions made at present in implementing the dispersion theory approach. In Chapter IV the validity of quantum electro dynamics is discussed and it is shown how possible deviations in this theory alter the nucleon form factor analyses. Two appendices are included with formal developments. We wish to thank the Air Force Office of Scientific Research, of the United States Air Force, for partial support in prepara tion of the manuscript. Воспроизведено в оригинальной авторской орфографии издания 1961 года (издательство "Oxford University Press").