Here is a story set in a more distant future when humankind travels to far stars routinely. Exobiology, the study of life forms beyond the earth, is a young enough branch of biology to be called "applied science fiction" as practiced by a science specialist of one kind or another. Studies in this field include characterizing hypothetical planetary environments, the native life with which might exist in such alien ecologies, and how such life might be observed, directly or indirectly. But short of actually traveling to the planets of other solar systems, the only life which we might be able to detect at a distance around other stars is intelligent life. Drawing on background from astrophysics, exobiology, planetary composition, Glen Cook creates an alien environment inhabited by intelligent life vastly different from us. And in what is also an exciting adventure story, he manages to raise serious ethical dilemmas about our possible relationship to such intelligences. G.Z.