But in any case, once the boys are attending different colleges, the matter loses importance—they both change their preferences to women—and other issues rear up. Ranjit pursues his twin interests of math and astronomy, in search of the ever-elusive simplified proof of Fermat's Theorem. He meets his future wife, the charming Myra de Soyza. But a bizarre yet ultimately beneficial monkey wrench gets thrown into his career. He's mistakenly swept up in a raid against terrorists and kept in a secret prison for two years. There, only his mind is free, and he manages to crack the proof. Released, he becomes famous, and his adult life is truly underway, with marriage to Myra, a host of important jobs and the birth of two children.

Parallel to and interspersed in the niches of this bildungsroman is a more cosmic thread. A race of superior beings known as the Grand Galactics, and their several clients, including the One Point Fives, the Nine-Limbed and the Machine-Stored, have determined through secret surveillance that mankind is too belligerent to be allowed to live. A genocidal armada is sent at relativistic speeds to exterminate mankind. But the long journey allows humanity to grow up a little, thanks to efforts by Ranjit, Gamini and others, and when the aliens arrive, big changes await them, offering hope for our survival.

Alien invasion, post-human paradise

The combined ages of these two authors comes close to 180 years. Does that mean that we should expect this novel to be backward-looking, retro and out of touch? Far from it! Both Clarke—until his recent death—and Pohl have maintained reputations for staying fresh, au courant, limber-minded and youthfully curious. The ideal state of an SF author at any age. Their first—and, regrettably, final—collaboration tells a truly 21st-century story, rich with genuine speculation and deft character development. Hot-button topics such as terrorism, peak oil, brushfire wars, artificial intelligence and others are ably parsed.

But this is not to say that the novel does not exhibit a certain old-fashioned flavor in its narrative tactics. It also harps—in a playful and agreeable manner—on many of the familiar tropes and themes that have distinguished the long careers of both men.

For Pohl's part, we get his fascination with mathematics, which extends back at least as far as his collection Digits and Dastards (1966). Likewise, his somewhat programmatic but insightful and mature psychological insights into a developing mind hark back to the first Heechee book, Gateway (1977). Missing overall is the inimitable sardonic and cynical tone of his most outrageous satires, although there are flashes. For instance, the ruler of North Korea is known as the "Adorable Leader."

As for Clarke's welcome hobbyhorses, we have plenty of megascale engineering, including a skyhook, moon colonization and solar-sail racing. More to the point is the whole Grand Galactics motif and the necessity for the human race to attain "childhood's end." (This book even repeats the resemblance of one of the alien races, the Nine-Limbed, to devils, which was a feature of that earlier classic.)

The narrative tone of the novel is more Clarke than Pohl, a kind of placid, measured, pace-by-pace progress report on the future of our species and the life of one man. Even dramatic moments, such as the anti-terrorist assault where Ranjit is captured, are doled out in measured cadences. The reader is often addressed directly, and a lofty coda jumps 13,000 years into the future of this future. So although the story always lures you forward, it does have kind of a Wellsian hand-holding aspect that reduces its immediacy.

But rest assured that Ranjit's odyssey will capture your delighted attention in its quiet yet intellectually and spiritually bold way.