Man and Superman is performed as a light comedy of manners, but Shaw intended the drama to be something much deeper, as suggested by the title, which comes from Friedrich Nietzsche's philosophical ideas about the "Übermensch".The plot centres on John Tanner, author of "The Revolutionist's Handbook and Pocket Companion", which is published with the play as a 58-page appendix. Both in the play and in the "Handbook" Shaw takes Nietzsche's theme that mankind is evolving, through natural selection, towards "superman" and develops the argument to suggest that the prime mover in selection is the woman: Ann Whitefield makes persistent efforts to entice Tanner to marry her yet he remains a bachelor. As Shaw himself puts it: "Don Juan had changed his sex and become Dona Juana, breaking out of the Doll's House and asserting herself as an individual". This is an explicit, intended reversal of Da Ponte's Don Giovanni; here Ann, representing Doña Ana, is the predator — "Don Juan is the quarry instead of the huntsman", as Shaw notes.Ann is referred to as "the Life Force" and represents Shaw's view that in every culture, it is the women who force the men to marry them rather than the men who take the initiative. Sally Peters Vogt proposes, "Thematically, the fluid Don Juan myth becomes a favorable milieu for Creative Evolution," and that "the legend...becomes in Man and Superman the vehicle through which Shaw communicates his cosmic philosophy"