I don't read much science fiction anymore, but this certainly rises to the level of Asimov and other golden age greats! The plot is exciting and keeps you reading page after page. The characters are likable and well developed. (At least the main characters are.) The science seems plausible. And the surprises keep coming. A really enjoyable read. One small complaint: I did find the hopping about in time somewhat confusing. Sometimes I wasn't sure if the part I was reading happened before or after the accident. But I think the author did that to preserve the big surprise for the right time, so I forgive him. Read this book. You won't regret it!