Near the center of a great spiral galaxy, where stars are much closer together than Earth's sun and its neighbors, a Human race developed. They were not identical to the Humans of Earth, but they were not very different, either. When these Humans discovered that waves of sub-space pi-tachyon particles could cross interstellar space faster than light, they realized they had found a link to the stars. A radio message that would have taken years to travel between stars could be sent with subspace communicators in months or even weeks. The Humans started broadcasting news of themselves to the neighboring stars, and soon found they weren't alone.
The Humans made contact with an inventive race of insect-like creatures called Vrusk, who had developed limited space travel decades earlier. One of the Vrusks' mining colonies had already contacted another race, the shape-changing Dralasites. The two races had been exchanging information for several years. The Vrusk and Dralasites were pleased to learn of another race. They sent a wealth of scientific information to the Humans. Using this new knowledge, the industrious Humans quickly developed interstellar spaceships.
The three races met in a large area of space known as the Frontier. There they also discovered the Yazirians, a race of tall, maned humanoids. Soon settled, worlds in the Frontier became melting pots for the four races, with dazzling mixtures of architecture and alien cultures. To supply the needs of these worlds, the first interstellar company, the Pan-Galactic Corporation, was formed. It developed interests everywhere, from scientific research to farming to spaceship building. PGC even created its own language, Pan- Galactic, which soon became the most common language of all races on Frontier worlds. Many large companies which started later were modeled on PGC, but none approach the size or power of the Pan-Galactic Corporation.
Then the Sathar appeared. No one knows where they came from or why. They attacked and destroyed lonely systems on the edges of explored space, moving slowly inward. Survivors described Sathars as wormlike creatures 3 to 4 meters long. That was all that was known about them, because they would rather kill themselves than be captured. As the danger increased, the Humans, Dralasites, Vrusk and Yazirians formed the United Planetary Federation (UPF) to defend their worlds. The mysterious Sathar were forced back, but before long they returned in a more sinister form.
The Sathar had learned that they could not beat the UPF in battle. Instead, they began hiring Yazirian, Human, Dralasite and Vrusk agents to sabotage interstellar trade and interfere with local governments. The UPF created the Star Law Rangers, an interstellar police force, to track the Sathar's agents from planet to planet and fight them on their own terms. But despite the efforts of the Rangers, the sly Sathar agents have become the most dangerous threat ever to face the United Planetary Federation and the frontier corporations.
STAR FRONTIERS adventures take place in an area of space called the Frontier Sector, or simply the Frontier. The Frontier contains 17 inhabited star systems, with a total of 23 colonized planets. Some of these planets have been claimed and settled by only one of the four races, while others were set up in cooperation and have mixed populations.
(Cited from the Alpha Dawn Digitally Remastered Rule Book p.1-2)