Charles Sheffield (June 25, 1935 – November 2, 2002), was an English-born mathematician, physicist and science fiction author. He was also a President of the Science Fiction and Fantasy Writers of America and of the American Astronautical Society.

A man from Earth's distant past is humanity's only hope for a future...Drake Merlin's wife, the love of his life, is dying of a rare, fatal disease for which there is no cure. Not now, in the 21st century. But surely in the future...For Drake there is only one solution: have Ana's body frozen until she can be cured. And he will go with her into the cryowomb. It is a desperate gamble born of folly, obsession...and love.Thus begins an epic journey across eons, as Drake is revived again and again, only to find that Ana is beyond help. Millions of years past his first sleep, he learns there is hope for her restoration--at the Omega Point, where the universe collapses, merging past and present. But first he will be awakened to become humanity's unwilling savior. For an alien menace is laying the solar system to waste, and only an anachronism from the days of human barbarism can save an enlightened race...