In her previous two books, THE BOOK OF SPECULATION and LIGHT FROM OTHER STARS, Erika Swyler has crafted works of science fiction that also tackle important philosophical questions. In her third novel, she continues to do so, in a dystopian narrative that explores social injustice, privilege, and the power and limitations of technology.

WE LIVED ON THE HORIZON takes place in a post-apocalyptic future. The setting is the city of Bulwark, which is controlled largely by a computer system called Parallax, described almost like an organic being: “the system known as Parallax breathes with wires in their walls, their pulse an ambient current, a tranquil electromagnetic field. They had begun not as a great expanse, but as a spark that grew with the city’s population, as their walls went up. They grew as did trees, from root and branch, burgeoning.”

"Swyler invites readers to reflect on our own society’s systems of social debt and the ways in which technology both enhances and threatens human flourishing."

Now, though, many years after Bulwark’s founding, Parallax is fully mature --- and powerful in ways that Bulwark’s human residents don’t fully understand. That includes even (or perhaps especially) Bulwark’s most eminent denizens, known as the “Sainted” due to the immense amount of social capital that they (and, more likely, their ancestors) have earned thanks to their good works and selfless actions.

Many of the Sainted now just rest on their laurels, but Saint Enita Malovis, known colloquially as “Stitch-Skin,” continues to add to her positive ledger by artificially generating (and then attaching) new body parts for the many workers who lose limbs or organs in workplace accidents elsewhere in the city. She is accompanied at all times by Nix, her house computer system. Because Enita, now in her 70s, never had children, she is mentoring Nix to continue her work after she dies. How does she do this? By creating a body for them, of course.

However, not everyone is as well set up as Enita. For those workers, they may never repay the debt they owe to society in Bulwark, which is why they have to throw themselves on Stitch-Skin’s mercy in the first place, rather than just going to a hospital. Enita knows all this intellectually, but sometimes she’s chosen to overlook other troubling aspects of Bulwark society. But when another Sainted is found to be murdered in his own home --- and the city’s systems seem to intentionally erase any data related to his death --- Enita’s former lover, Saint Helen Vinter, is convinced that this new mystery is part of a larger web of troubling developments, indications that all is not well in Bulwark.

At times, WE LIVED ON THE HORIZON can feel as leisurely as a conversation between two old friends, as Enita and Helen take their own paths to growing realizations about their society and their privileged place within it. Readers eventually will grow accustomed to the pensive pace of the book, which is also narrated by many different entities, including AI systems like Nix and Parallax. That’s not to say, though, that the novel is relentlessly slow. It’s often interrupted, sometimes in dramatic fashion. A woman who’s discovered to be a Body Martyr (someone who repeatedly donates organs in order to remedy her social debt) shows up, gravely injured, on Enita’s doorstep, sending much of the story’s action into motion.

Throughout the book, Swyler invites readers to reflect on our own society’s systems of social debt and the ways in which technology both enhances and threatens human flourishing.