The Reach is a big and perilous place, but it's also an optimistic view of a 30th century society which views our modern times and troubles as the "Second Dark Age" of mankind.
This setting is not an engine for political preaching, only the creation of engaging stories of adventure, mystery, and drama.
The Angels' Reach is not, in the grand scheme of the cosmos, a very big place. Stretching across a few hundred light-years of the Orion Arm of the Milky Way galaxy, the Reach is bounded by the Gaps on two sides, and grows slowly along the arm by way of the Coreward and Rimward Frontiers.
The Reach (its denizens refer to it as such) is defined by the general extent of human habitation, though some colonial expeditions do venture out into the star systems beyond the Frontiers, and even across the Gaps to the neighboring arms of the galaxy. What becomes of these brave - and perhaps foolhardy - people is not always known; some vanish without a trace, intentionally or otherwise.
By the dawn of the 30th century, the undisputed masters of this section of space are humans, but even as recently as the mid 29th century this was not the case. For two hundred years, much of what is now known as the Reach was dominated by the Rattanai Imperium, and towering, iron-boned Rattanai make up the largest group of nonhuman residents of human space.
There are other xenosapients as well - Atro'me in their tight-knit clades, struggling to rediscover their lost cultural identity, nomadic Reachers plying the spacelanes in their mercantile habitat-ships, and of course the stern, secretive Angels, the self-appointed alien guardians of old Terra. Ruins and artifacts found throughout the Reach hint that in ancient times the region was ruled by another powerful culture now extinct, known to human science only as the Xenarchs.
Human science learned much less from the remains of the Atro'me armada than they had first hoped, but what was learned still caused several revolutionary advances in the technologies used in human spacecraft. Of the technologies scavenged from the alien warships, the most lasting would be the so-called Grinner Reactor - a matter-antimatter annihilation powerplant far more capable and far more stable than previous human-built fusion systems. This device would become the power plant of the Great Expansion.
With iterative improvements on the Xiou-Edwards system and newly colossal power output of Grinner Reactors, human-crewed interstellar travel was suddenly possible in weeks or months, not years. Planet at Centauri, already the site of a permanent scientific expedition, was opened to colonial settlement within five years of the end of the Atro'me invasion, and other systems followed - systems which would become, by the end of the Expansion, the pillars of the Core Worlds.
Though expansion into the ...
Though the arms-race among the Signatories promised war, when that war came in 2293, it was not the one anyone expected.
The Atro'me - the Grinners, as they were known at the time - were much more like humans Reachers, and when they first appeared, this made them seem a manageable threat. Raiding the outer Kuiper Belt worlds in increasing numbers as their dispersed fleet followed the reports of the first ships, these aliens came to Sol only to plunder, destroy, and conquer. The Signatories put aside their differences to deal with what was seen as a relatively minor threat - after all, their technology was not terribly more advanced than that of mankind.
Once the main "Grinner" armada had reached Sol, the few remaining Kuiper Belt outposts fell quickly. The Signatories, forced into an uneasy alliance, joined their fleets in a desperate effort to repel the invasion. The Grinners seemed to want nothing of humanity, desiring only to conquer Sol for themselves. For two bloody years, the Signatories ...
Before the Reachers departed Earth, physicist Lin Xiou and aerospace engineer Alexander Edwards had already built their famous prototype machine based on Reacher science - a device to move between locations without crossing intervening space by folding the Cosmic Fabric upon itself. The Xiou-Edwards drive family born of their invention will remain in use (undergoing many revisions and updates) eight hundred years later, though for several generations its ability to power true faster-than-light travel was theoretical rather than practical.
The success of the Xiou-Edwards project was at first hushed up, but not for long. Against the orders of their governmental masters, these two visionaries, exposed as they were to Reacher ideas beyond the scientific, did the unthinkable - they open-sourced their invention, releasing its schematics worldwide. The few large interests still involved in the WSA pulled out to build their own space programs once more, using this technology and others derived ...
