Much excitement has arisen throughout the galaxy over the exploration mission to Jupiter's moon, Amalthea. Led by the renowned Professor J.Q.R. Forster, the dangerous expedition will lead its members to the surface of this strange moon--and beyond. Sparta's mission is to monitor the trip on behalf of the Board of Space Control. The fifth volume in a series of science-fiction thrillers evolving from the works of Arthur C. Clarke, grandmaster of science fiction.