Space entrepeneur Randy Hunter discovers a kind of space-dwelling plant composed of negative matter, which allows him to develop interstellar spaceflight and time travel, not to mention acheiving all of his dreams, winning the girl, foiling his drug-addicted rival, and becoming an all-around great guy. ... Author Robert L. Forward never lets us forget how wonderful and brilliant he thinks his hero is, which came off as more than a little self-congratulatory since I couldn't shake the feeling that he was meant to serve as an alter-ego for Forward himself. There is much juvenile one-upmanship between Randy and his cartoonish arch-rival, Oscar, who is just as bad as Randy is good and whose dislike is never explained as anything more than jealousy (but then, who wouldn't be jealous of such a terrific guy as Randy). I found the key plot device of the Silverhairs to be ludicrous and uninteresting. The sole saving grace of this book is some fascinating business toward the end concerning time travel and the interaction between the Randys of various time periods. Had this aspect of the story been more prominent, it would have been a better book, but instead it is buried among juvenile characterizations and dull plotting.