Another galactic odyssey from the author of Dragon's Egg (1980). After a tedious introduction to the cast, Forward offers a scientifically plausible theme: a manned interstellar mission to Barnard's Star, in a ship equipped with solar sails and boosted to high speed by space lasers drawing their power from stations on Mercury. Moreover, Barnard's Star has a complex planetary system including a feasible (if absurd-sounding) double planet, Rocheworld, where numerous odd phenomena occur: Rocheworld's cold water-ammonia oceans are inhabited, for instance, by colloidal whale-like aliens. So far, so good. Thereafter, however, the plot follows a feeble alien-contact space-opera formula--as the humans explore Rocheworld, discover the aliens, and survive various dangers. And Forward's general approach is often sophomoric: aliens who talk and act like surfer/preppies; a huge but faceless cast-of-characters; and a welter of technical detail. Humdrum storytelling, with some promising scientific extrapolation made into an uninvolving exercise.