The Mirage, by Matt Ruff (hardcover, $25.99)

The story begins a few years after the World Trade Center's twin towers fell, destroyed by airplanes flown by terrorists. The Homeland Security Department has been created, and our hero, Mustafa al Baghdadi, works for it, along with his friends and colleagues, Amal and Samir. Mustafa's wife, Fadwa, died in the chaos of that day, November 9, 2001.

11/9. Not 9/11. Why? Because the twin towers were in Baghdad, not New York City. The UAS -- United Arab States -- were attacked, not the USA, which doesn't exist. North America, where the United States of America should be, is a jumble of independent countries, including the country of Texas. Everywhere in North America are Christian fundamentalist and crusader groups and political parties. It was one of those groups that propelled the planes into the towers in Baghdad.

Although there are occasional comic references to things like Six Flags Hanging Garden Water Park and Green Desert instead of the singing group Green Day, Matt Ruff doesn't cross the line into parody or slapstick. He wants to show that what we consider to be all-American references are now UAS references. What was once USA is now UAS. That's not to say that the switch is complete. The UAS is almost all Muslim, but Christianity is tolerated, Middle Eastern Christians being subjected to the same suspicion that Muslims receive in the USA today.

The UAS also still has Saddam Hussein, a gun-toting, high-level gangster. It also still has Osama bin Laden, the fanatical right-wing head of al Qaeda. In the name of protecting national interests, the UAS is no better at resisting the temptation to torture its suspects than the USA is. Familiar names dot Ruff's landscape: Uday and Qusay, Nouri al Maliki, Muqtada al Sadr, David Koresh, Timothy McVeigh, Tariq Aziz, and a rumpled Donald Rumsfeld, whose final scene seems pathetically appropriate. Other real people are referred to obliquely: the Quail Hunter and the man from Crawford, Texas, for instance.

So what is really different?

Mustafa, Samir and Amal take their jobs seriously. They try to play within the rules, which is more than can be said of the corrupt Baghdad police, but they eventually find that the rules are changing. Captured terrorist artifacts indicate a bizarre scenario: The twin towers that were destroyed were in New York City and the terrorists were Arabs. Mustafa and others are occasionally dizzy, accompanied by a sense that something is wrong. The trio first accidentally and then purposely dig to find out who or what is behind the hidden world.

Although The Mirage progresses from a spy thriller to an increasingly out-of-kilter storyline, it's never frivolous. Ruff manages to hold a serious tone throughout. His final chapter provides a moral to his fable: Be careful what you wish for.

This is a solid, thoughtful, well-researched novel by someone whose head must visibly crackle and sparkle with all of his creative thoughts.