The premise of Matt Ruff's new novel probably could have gotten him arrested back in the panicked, paranoid days of 2002. The Mirage (Harper, $25.99) imagines a world where the dominant power is the United Arab States. After Christian fundamentalists topple the Tigris & Euphrates World Trade Towers in Baghdad on 11/9/2001, troops from the UAS flood into the fractured nations of North America to find weapons of mass destruction that may or may not exist. The invasion is highly controversial, and by 2009, the UAS is torn between citizens who support isolationism and more hawkish forces—including beloved Senator Osama bin Laden—who want to see Christianity utterly destroyed. At the same time, Muslims are becoming more lax in their worship and social mores (many people don't even stop their busy workdays to respond to the five calls to prayer that sound around the city), and angry fundamentalists complain that the UAS's necessary religious roots are withering away.

Ruff, a local writer, embraces this twisty concept with an attention to detail that suggests many months, more likely years, of fervent research. He imagines the life of a federal agent named Mustafa al Baghdadi, who, in the patriotic days after 11/9, shifts his focus from arresting smugglers of illegal alcohol to the more serious field of Arab Homeland Security. Al Baghdadi uncovers a plot that stretches from the highest powers in the UAS all the way down to the scuzziest crime lord in Baghdad—a small-time loser with airs of grandeur named Saddam Hussein. Along the way, al Baghdadi discovers artifacts (mostly paper items, including the front page of a nonexistent newspaper called the New York Times announcing the destruction of a twinned pair of nonexistent skyscrapers in New York City) that suggest there is another world out there where the script has been flipped.

Fans of genre fiction might find some parallels to The Man in the High Castle, the promising first book in an aborted duology or trilogy by Philip K. Dick that imagines a world where the Nazis won World War II. It's a fair comparison—many of Ruff's books, especially the identity-annihilating espionage thriller Bad Monkeys—owe profound debts to Dick's work. But unlike Dick, Ruff has never been afraid of temporary immersion in disparate genres, bouncing between sci-fi, literary parody, and even romance from novel to novel and, at times, chapter to chapter. Using the framing device of a military-style thriller enables him to cram The Mirage with concepts and suggestions of whole other novels beckoning at the fringes of al Baghdadi's story.

Ruff is a world-class world builder who, perhaps better than any other writer, can create exotic, mysterious worlds and communicate their unique rules and consistent logics both clearly and concisely. Ruff cleverly constructs UAS analogs to our western world: He prefaces certain chapters, for example, with excerpts from the Library of Alexandria, the UAS version of Wikipedia, providing the reader with a crash course in concepts like temporary marriage, the European state of Israel, and more in stilted, crowd-sourced prose studded with hyperlinks. ("Female infertility is one of the most common grounds for divorce...") Ruff strings little teasing morsels throughout the narrative, as when Mustafa scours a bookstore looking for a suspect, walking by a stack of remaindered copies of "the post–November 9 best seller, now heavily discounted, Christianity for the Ignorant."

But there's more to The Mirage than a lighthearted game of spot-the-reference. The narrative moves to war-torn North America, where we are introduced—along with al Baghdadi—to the Christian insurgents fighting against UAS forces with weapons of terror. We meet the familiar figures of the Christian insurgence, and it becomes apparent that The Mirage isn't just an object lesson in geopolitics; it's a secret history, a magic mirror allowing glimpses into the effects of religious fundamentalism of all types on the United States over the last 50 years.

Later in the book, a tense scene featuring rebels attacking a caravan of heavily armored military vehicles so closely resembles familiar sequences in films and TV shows set in Iraq that you have to remind yourself that "our" troops are fighting on the "other side" this time around. Being forced to keep the perspectives straight feels like stretching a never-used muscle; it leaves your empathy haggard and suspicious.

When the time comes for Ruff to draw The Mirage to a close, the narrative confronts several necessary rough patches—you can't jumble entire universes without violating suspension of disbelief once or twice—but that sustained feeling of reversed discovery, coupled with the explosive prose of a very good thriller, is a marvelous trick to play on a reader. The Mirage might not get Ruff arrested as an enemy subversive, but it's likely to earn him a passel of conservative evangelical hate mail. That's a sure sign that he's doing his job right.