James Patrick Hogan, . . Baen, $26 (432pp) ISBN 978-0-7434-3581-9

This clumsy sequel to Hogan's Cradle of Saturn will produce more anguished readers than satisfied ones. Maverick engineer Landen Keene has led his band of survivors from an Earth where civilization has been wrecked by the passage of a mysterious planetary body named Athena. They land among the Kronians, human settlers in the asteroid belt and Saturn's moons who have developed a utopian society and (conveniently) anti-gravity. Unfortunately, some of the other survivors from Earth, led by Kurt Zeigler, form a faction called the Pragmatists, who want to jettison Kronian ideals in favor of competition, money, militarism and a resettlement of Earth. With the help of the handful of surviving and implausibly primitive inhabitants of Earth, under the boy war-chief Rakki, the Pragmatists are making an alarming amount of progress. Luckily, the quick-thinking Keene can turn to Kronian loyalists who've infiltrated the Pragmatist ranks and to Pragmatist dissidents for help in thwarting the menace. Big action (or at least disaster) scenes don't make up for uneven pacing, the fringe cosmology of Immanuel Velikovsky, wooden characterization and excessive exposition. (June)