Larry Niven's Known Space stories have been an icon of high-concept SF adventure since the 1960s. Praised equally for both accurate hard SF and for creating unique alien psychologies, these talents culminated in the award winning novel Ringworld, which has been in continuous publication since its initial introduction.

Fans clamored incessantly for sequels and over the years Niven has delivered, first with "The Ringworld Engineers," "The Ringworld Throne" and more recently with "Ringworld's Children."

For those that somehow missed these stories: the ring world is an enormous construct completely encircling its star with a diameter roughly equivalent to Earth's orbit and inhabited by a variety of sentient species. The initial and subsequent novels follow various scouting parties sent to the ring to determine its origin and its purpose.

The expeditions to the Ringworld are organized and led by the alien Nessus, a Pierson's Puppeteer. The Puppeteers are an enigmatic and manipulative species that economically dominate Known Space, a region of the galaxy that includes Earth and her colonies.

Other stories in the Known Space canon inform us that the Puppeteers have a secret; an enormous explosion has occurred in the center of our galaxy and a wave front of lethal radiation, capable of obliterating all life, is swiftly spreading out from the core. The Puppeteers have set their worlds in motion in order to escape the lethal wave. The Ringworld lies in the path of this migration of worlds and the scouting parties have been organized to determine the potential threat to the migration that it represents.

In these previous Known Space stories and novels we learn a few important things about the puppeteers; they're descended from herbivores, a herd psychology dominates their society and they're paranoid – perhaps justifiably so.

Fleet of Worlds takes place approximately two centuries prior to the initial visit to the Ringworld. Its central character is again Nessus (Puppeteers apparently live a long time) and most of the story revolves around his interactions with a small group of humans who are being trained as interstellar scouts.

The human characters are descendants of the crew and colonists of the Long Pass, an interstellar colony ship rescued by the Puppeteers after it was found disabled and drifting through space. Graciously, the Puppeteers have deeded a portion of one of their farm worlds to these humans, who tend the farms in exchange for the support and protection of their alien mentors.

Nessus has been chosen as the go-between because of his political affiliations and because of his mental illness; only a warped puppeteer could handle the stress of interacting with a wild species and the equally damaging effects of removal from the herd.

Due to the requirements of their training, the human scouts are released from their isolation on the farm world and are exposed to aspects of Puppeteer society they had previously been unaware of. Like all good monkeys throughout the cosmos, they begin asking questions, most of which Nessus doesn't want to answer.

I've been a faithful fan of Niven for years and eagerly looked forward to finding out more about the Puppeteers. Given a chance to take a free tour of their Klemperer Rosette fleet of worlds, I couldn't resist and I wasn't disappointed.

Not being familiar with Edward M. Lerner's previous work, I can't say how much of an impact he had on this collaboration; Niven's other collaborations (Pournelle, Barnes, others) appear seamless and such is the case here. The mere fact that Larry chose to work with Edward will prompt me to pick him up in the future.

One of Niven's hallmarks are Gordian-knot plot elements, onion layers of revelation, new theories regularly supplanting old ones as new facts come to light, facts that we only learn as the characters become aware of them.

And then there's the Fleet of Worlds. The home world lit and warmed solely by its billions of inhabitants and their industries, encircled by a ring of farm worlds, its dark landmasses highlighted by strings-of-pearls cities, set in motion by uber Puppeteer technologies and sailing inexorably out of our galaxy. It's majestic and awe-inspiring and a perfect setting for the mysteries that unfold throughout the novel.

The true revelatory experience to be had from Fleet of Worlds is the exposition of Puppeteer society; few others can convey true otherness as subtly and surprisingly as Niven does as when, for example, we gain a much deeper understanding of Puppeteers and their society through the simple act of defecation.

Fleet of Worlds has all of the elements that Niven fans have come to expect as their due: high technology, engineering on a truly massive scale, psychological surprises, mysteries to be unraveled that lead to greater mysteries. The novel works well as a standalone, will be a treat for Known Space addicts and is the perfect entre for those who are planning to visit Known Space for the first time.