One of the leading luminaries of hard science fiction (Mars, 1992, etc.) teams up with newcomer Austin for this "fix-up" novel, some parts of which appeared as long ago as 1978. A spacegoing empire dedicates its resources to preventing the death of Earth's sun, the star under which humanity originated. A dying emperor is won over by the young woman who has discovered the process that makes possible the rejuvenation of a star, and passes the task on to his son as the great undertaking of the race. The imperial capital is moved to Earth's moon, and the project set into motion. But all too soon, the grand imaginative scope of the beginning chapters here drifts into business as usual. Instead of an epic sweep, the plot winds down into weakly connected episodes (sabotage by fanatics, rivalry between the new emperor's sons, a civil war on a distant colony) before returning to its original direction with a test of the solar rejuvenation process. Despite an audacious premise, a strong cast of characters, and Bova's knack for political intrigue, this is finally a disappointment.