Larry Niven & Jerry Pournelle – Moties

In 3016, the 2nd Empire of Man spans hundreds of star systems, thanks to the faster-than-light Alderson Drive. No other intelligent beings have ever been encountered, not until a lightsail probe enters a human system carrying a dead alien. The probe is traced to the Mote, an isolated star in a thick dust cloud, & an expedition is dispatched. In the Mote the humans find an ancient civilization--at least one million years old--that has always been bottled up in their cloistered solar system for lack of a star drive. The Moties are welcoming & kind, yet rather evasive about certain aspects of their society. It seems the Moties have a dark problem, one they've been unable to solve in over a million years.

25 years have passed since humanity quarantined the mysterious aliens known as Moties within the confines of their own solar system. They have spent a quarter century analyzing and agonizing over the deadly threat posed by the only aliens mankind has ever encountered-- a race divided into distinct biological forms, each serving a different function. Master, Mediator, Engineer. Warrior. Each supremely adapted to its task, yet doomed by millions of years of evolution to an inescapable fate. For the Moties must breed-- or die. And now the fragile wall separating them and the galaxy beyond is beginning to crumble.