This is a translation of Ferenczi's well-known work Versuch einer Genitaltheorie. It is a work that many will consider displays most vividly some of Ferenczi's most valuable and least valuable qualities. One cannot deny that it has the quality of originality and daring, but whether that of critical power is as prominent is very much open to question. It is certainly good to see it translated for those who do not already know it and we shall hope that the stimulating elements in it may fall on fruitful soil.