The story is set approximately 9,600 years in the future (approximately 11,600 C.E.). As is made clearer in McDevitt's later Alex Benedict novel Seeker, during the course of recorded history, human civilization has spread through a substantial part of the Orion Arm of our galaxy. The novel is concerned with two time periods – the present of the principal viewpoint character, Alex Benedict, and a period approximately 200 years before his time, which is viewed through back-story.
Humanity discovered the ruins of one alien technological civilization, and encountered one that at the time of the story is alive and thriving, the Ashiyyur. The sphere of Ashiyyur worlds is described by the author as abutting the worlds of human civilization along the Perimeter – first contact was made at least several hundred years before the time in which the back-story is set. McDevitt conceives the Ashiyyur as being at approximately the same technological level as humans, and in fact humanoid – bi-laterally symmetrical, bipedal, larger than average for human, of two genders, descended from predators, and interested in the same kind of real estate as humans. Most significantly for the story, they are also incapable of audible speech without mechanical aids, and are nicknamed “Mutes” by humans as a result. The Ashiyyur are telepathic and have evolved a society based on that form of communication. They have the ability, with some difficulty, to “read” human minds and emotions. Ashiyyur civilization is described as being much older than human civilization (approximately 75,000 years versus perhaps 15,000) but as having developed much more slowly. It is important to the back-story that to the Ashiyyur, human dynamism and exuberance appear threatening and humans are aggressive, untrustworthy, and unethical.
McDevitt describes human civilization at the time of the back-story as spread across many worlds, most of which were independent of the others. All maintained sentimental ties with Earth, but difficulties of interstellar travel and local parochialism ensured that there was no central government. Many human worlds maintained their own armed forces but again there was no central direction. Communication between worlds was limited to travel by interstellar ships, which used magnetic drives for short and medium distance travel within star systems and Armstrong interstellar drives by means of which ships could travel between star systems through “Armstrong space”. Both at the time of the back-story and in the protagonist's time, navigation using Armstrong drives is sufficiently imprecise that ships must for safety reasons emerge from Armstrong space well away from stars and planets and travel substantial distances (and times) using magnetic drives. In addition, and partly as a result, travel through Armstrong space is time-consuming – as described in the novel, a voyage of 3,000 light years takes about seven months, of which about five months time is spent in Armstrong space. It is important to the story that some individuals, like Alex Benedict and most Ashiyyur, react physically badly to the transitions into and out of Armstrong space.
As described in the back-story, following first contact with the Ashiyyur, there was increasing friction between human and Ashiyyur civilizations, evolving from a “cold war” into an increasing number of small and then larger military clashes in which the Ashiyyur generally prevailed. The fiercely independent governments of the human worlds responded to the Ashiyyurian challenge largely by dithering and self-deception about the threat. A few human worlds, led by Dellaconda, reacted militarily by forming a small military force, based at first mainly on the Dellacondan navy, to wage a guerrilla war known as "the Resistance" against the Ashiyyur. The back-story begins at this point in history, although it is not told in strictly chronological sequence.https://en.wikipedia.org/wiki/A_Talent_for_War