Hundreds of years later, the Puppeteers have added four other Nature Preserve worlds to create a Fleet of Worlds, and on one they have established a human colony whose inhabitants have been taught that the Puppeteers saved them and do not know their planet of origin. The Puppeteer Nessus, insanely brave by his race's standards, is mentor to a crew of three colonists—Kirsten, Omar and Eric—who serve aboard the Explorer to scout ahead of the Fleet and identify potential dangers. They detect radio signals from a frozen ocean planet and discover starfish-shaped aliens they call Gw'oth who are just learning to get to their planet's surface but are developing new technology at an amazing pace. Kirsten, the ship's navigator and mathematical genius, becomes fascinated with the Gw'oth but complies with Nessus' orders to prepare an asteroid to destroy the Gw'oth if it is determined they are a threat. She has begun to suspect, however, that the Citizens have been lying to the human colonists about their true past and their knowledge of the humans' home planet.

Back on the Puppeteer homeworld, Nessus reports to Nike, a high-level bureaucrat in the Experimentalist party. Nike, with whom Nessus is secretly in love, is scheming to get his party to take control of the world government currently led by the Conservatives. When Nessus is assigned to travel to Earth's system to continue their clandestine manipulations of Earth society, Kirsten convinces the other Explorer crewmembers to assist her in investigating the true history of colonists. Using the Puppeteer local teleport system, they find a secret Human Studies Institute and begin to build evidence that shows that Citizens have lied to the colonists for centuries and are their captors, not their benevolent saviors. The crew of the Explorer and the colonist leaders must determine how to use this information in a way that will not lead the cowardly Puppeteers simply to destroy them.

A new mapping of Known Space

For 40 years, Larry Niven has been setting most of his science-fiction novels and short stories in a future history he calls Known Space. It has proven to be a very fertile milieu, with stories set in both the distant past and the distant future, featuring a number of fascinating alien races, including the cowardly and manipulative Puppeteers and the brave and quarrelsome Kzinti, which participated with humans in the exploration of Ringworld, the giant alien artifact that is Niven's most memorable creation.

Fleet of Worlds is the first of a two-novel prequel to the Ringworld novel series. (The second novel will be called Juggler of Worlds.) It is the first Known Space novel to be written with a co-author, Edward M. Lerner, and a very worthy addition to the ongoing Known Space future history.

Niven's aliens are among the most memorable of the many alien species create in science fiction, and the Puppeteers are arguably the most interesting of his alien creations. They are an iconic example of aliens that are a serious threat but in no way really evil; their actions are perfectly reasonable given their risk-averse nature, evolved as they are from herd animals. (They even are politically correct enough to hide from other races the secret of their basic reproductive biology, which involves a pair of intelligent males and a female of very low intelligence who expires during reproduction.) The political system for the Puppeteers is also fascinating, if somewhat simplistic by human standards. In this novel, the Gw'oth are another startlingly original alien race that makes sense once the secret to its rapid development is learned, and I can't help but hope that it plays a strong role in the next novel in the series.

If there is a weakness to this novel, it is any not lack of logic or verisimilitude in the setting and narrative, but possibly just the opposite. If you are intimately familiar with Niven's past Known Space novels and stories, virtually everything in this novel is reasonably and logically predictable. There are few real surprises, and too few compelling moments where the knowledgeable reader can't wait to see what could possibly happen next. (Readers without background knowledge from previous novels, on the other hand, are likely to find the narrative confusing and to have a hard time understanding what is really happening and why.)

Veteran science-fiction readers familiar with Niven's past work will nevertheless find this new novel in the Known Space series essential reading.