During the 1970s Larry Niven was one of my very favorite Science Fiction authors. His "Known Space" setting was the launching pad for many excellent novels and short stories, and this established Niven as a leading author of "Hard SF." The "Known Space" universe featured a dazzling, and not implausible, future for the human race and even better, the aliens of Known Space really were alien. The Kzinti and the Puppeteers, to name two of the principal alien races, are truly imaginative.
This novel is set in "Known Space" and begins at a time shortly before the human race has discovered hyperdrive, although most of the story occurs after that time. A group of humans in space is essentially kidnapped by the Puppeteers, who intend to use these humans and their descendants as a slave race, albeit a fairly well treated one. The Puppeteers will use the humans in certain labor functions, and also as interstellar scouts, since the highly risk-averse Puppeteers are not well suited for risky jobs of this type. "Known Space" junkies will recall that the Puppeteers are fleeing our Galaxy because the galactic core will eventually flood the entire Galaxy with deadly radiation.
The novel essentially revolves around two themes. Firstly, the human servants are finding out that the Puppeteers have lied to them about their origins, and about humanity. Secondly, the Puppeteers are worried that other races, humanity included, will spot their migrating worlds and threaten them. This causes the Puppeteers to act preemptively and aggressively, and frankly, unwisely and implausibly.
The real core of this novel is to give the reader far more insight into Puppeteer politics and society than we ever got before. Some of this is interesting, but not enough to carry the novel. Unfortunately, the novel also highlights Niven's enduring weakness at creating three-dimensional characters. Here the characters are flat and forgettable. In some of his other stories Niven sometimes gets around this by writing in the first person (i.e. the Beowulf Schaeffer stories), but not here, although I wonder if that might have worked here. Niven fails to capitalize on his former strengths as a writer (skillful use of scientific prognostications and the effect of technology on the evolution of society) because there really are not any interesting speculations about society or the future of humanity (or even the future of the Puppeteers) contained in this novel.
Overall, this one was good enough to finish, but not good enough to read again, and this distinguishes it from most other "Known Space" writings, which I have read many times. It is impossible not to notice that almost everything Niven has written over the past 20 years has been in collaboration with other authors. It is almost as though he is more interested in the social network of his author friends than in writing to please the reading public. That is my perception, at least, because Niven's offerings for the past two decades have not been nearly as good as his earlier writings.
Overall a disappointment, although Niven fans will probably enjoy this one.