FROM THE FIRST, with two series of novels whose ambitious narrative arcs moved from near-future Earth settings to distant planets and increasingly strange cultures populated by posthumans and a variety of artificial intelligences, Ken MacLeod’s science fiction has been notable for hybridizing political thought experiments with the possibilities offered by transgressive technologies. His more recent works share this trait, but have been resolutely Earth-bound and concerned with exploring contentious contemporary issues: the war on terror in The Execution Channel; the aftermath of the collapse of the Soviet Union in The Restoration Game; state surveillance in Intrusion. The Night Sessions tackles one of the thorniest issues of all, religious extremism, combining a police-procedural mystery with speculations about the nature of religious faith and artificial intelligence, and featuring a near-future setting that makes a bold break with the present.

It’s a couple of decades after the Faith Wars culminated in the nuking of California by American fundamentalists and a war involving tactical nuclear weapons that rendered Israel and Palestine uninhabitable. Organized religions have been stripped of their temporal powers and political influence — the Catholic Church has been bankrupted by an African AIDS class-action lawsuit and the Vatican is run by an occupying force — and a Second Enlightenment has created a secular, high-tech paradise full of the shiny toys from futures of days long past, when the Apollo program and 2001: A Space Odyssey promised easy travel to other planets. There are bases on the Moon and Mars, and Jupiter’s moon Europa. Space elevators carry cargo and passengers into orbit. Orbiting sunshades are an important part of the struggle to ameliorate the effects of climate change. Robots are ubiquitous, and a small number of artificially intelligent machines, many of them veterans of the Faith Wars, have gained true self-awareness. If religion has been proven to have had a ruinous effect on human history, MacLeod asks, what would happen when intelligent robots get with God? What kind of religion would they create?

The Night Sessions, then, is a clever variant on the rise-of-the-machines subgenre that spans the Darwinian struggle of the Terminator films, and the stranger futures in which artificial intelligences achieve a technological Singularity and become as powerful and incomprehensible as gods. A considerable part of the mystery that drives the narrative of The Night Sessions is where it lies on this spectrum, a mystery that’s resolved through the police-procedural strand of the story and the patient unpicking of what appears to be a resurgence of faith-inspired terrorism. Grounded in a thoroughly realized Edinburgh that makes good use of the city’s deep history of internecine religious conflict, its protagonist, Adam Ferguson, is the mirror image of Ian Rankin’s Rebus and other truculent, non-conformist cops: a sober family man who is ashamed of, although not especially traumatized by, his involvement in the brutal repression of religion in the aftermath of the Faith Wars, and shares a nice line in banter with his robot sidekick, Skulk. Two clergymen are murdered, a rogue Faith War veteran is implicated, and the latest in a series of incendiary pamphlets about a “Third Covenant” starts the plot’s clock ticking by threatening to extend a war against apostate churches t...