Taking proper care of the body today, Ray Kurzweil believes, is a necessary step on the path to immortality for himself and his fellow baby boomers.

In 20 years, he predicts, biotechnology will be able to block the circuits that cause disease and will radically slow aging.

After that, what he calls the “full blossoming of nanotechnology” will allow us to replace the fragile and disease-prone cells we were born with, swapping our fading neurons with nano-engineered neurons that keep our memory forever sharp.

He plans to be around for both those revolutions, whenever they occur.