Echoes of Issel

Continuing the Unified Worlds series begun in Ganwold's Child (1995), Thornley's second novel traces the further adventures of Tristan Serege as he and his mother are united with his father, the commander of the United World's most elite space-attack forces. The narrative energetically mixes personal problems and crises, political intrigue and military action, though it lacks the absorbing alien anthropology of its predecessor. An emphasis on characters' emotional problems may initially dismay readers drawn to the derring-do prevalent in that earlier yarn, but here the author adds important SF twists, and allows suspense, as well as military and political action, to run high. Fans of military SF will especially enjoy reading about Tristan's training, some of it based on Asian martial arts. With writing that's clear and expressive, and characters that start out strong and gain depth, this proves to be a spaceworthy sequel. (Mar.)