A suicidal eccentric American billionaire industrialist accidentally crosses paths with a disembodied alien intelligence he calls Ell. The two team up.
Through complex space/time machinations he is able to download his 70-year-old self into his 10-year-old body of his youth. Through a large portion of the book we accompany him reliving his life a second time around, trying to make changes to the way it went the first time.
He ends up inventing a time/space travel machine. Eventually he uploads his own identity into a machine and starts becoming a disembodied intelligence himself. Ah, eternal life!
For my taste, there was too much psychobabble about disembodied intelligence, but in the end, I enjoyed reading the book, it was quite well-written, and I must say that it’s required reading for anyone interested in the time travel genre.