The subject of true hermaphroditism or bisexuality is one that for ages has absorbed the master minds of science and philosophy; and the true cause of the phenomena of hermaphroditism is one of the greatest of mysteries known to past generations. In this work on bisexual man, the authors set forth a hypothesis as to the descent of the present human race from ancient bisexual ancestors, contending that there has been an evolution of separate sexes from bisexual man, and that the present males and females are but the deteriorated representatives of once superior human creatures; also that we have so long assumed to be a rare freak of nature is really but a partial return to the original type of perfect bisexual man.