Edge of Dark

Cooper%E2%80%99s awkward trilogy launch assumes familiarity with the world of her Ruby%E2%80%99s Song series and leaves the new reader puzzling, for much of the book, over terms like "the Glittering" and "the Diamond Deep." Humans who experimented with the hybridization of human and machine were exiled to "the deep dark" from which they have now returned, infinitely powerful. They require warmth, or energy, or matter; it%E2%80%99s never made clear. Standing against this Borg-like threat is Nona, a rich young woman given a spaceship by a richer aunt and thus made captain of the vessel, despite having no background or training in "captaining" nor showing any apparent affinity for it. The book is replete with contradictions: after Chrystal, Nona%E2%80%99s childhood friend, is killed and her memory is uploaded into a nonorganic machine, she still somehow feels pain; the invaders are all-powerful and indifferent to human life, yet willing to negotiate treaties. The characters are undeveloped, the politics are muddled, and there is little in this book to inspire longing for the next installment. Agent: Eleanor Wood, Spectrum Literary Agency. (Mar.)