From the bestselling author of The End of Nature comes a passionate plea to limit the technologies that could change the very definition of who we are.

Reporting from the frontiers of genetic research, nanotechnology and robotics, he explores that subtle moral and spiritual boundary that he calls the "enough point."

Presenting an overview of what is or may soon be possible, McKibben contends that there is no boundary to human ambition or desire or to what our very inventions may make possible.

"We need to do an unlikely thing: We need to survey the world we now inhabit and proclaim it good. Good enough."