In this late work, Shaw examines many contemporary issues under the broad rubric of evolution and then illustrates his opinions in five brief plays set in widely separated historical periods, beginning in the Garden of Eden and ending in the year 31,920 A.D. The unifying principle in this historical survey is the notion that the survival of humankind depends on increasing our lifespan to at least 300 years, a period permitting us to grow to maturity. The ultimate question that the mature cast of characters grapple with is what is to be the next significant step in evolution. Mere longevity simply enables them to ask this question. We see in the final play the beginning of the answer: first, escape from the social experiment, which began with Cain, a long and toilsome journey towards anarchy, and then gradual liberation from the grossness of physical imperfection and at last from bondage to flesh itself into immortality. What might lie beyond that, the author leaves to the imagination. - Summary by Thomas A. Copeland