Amanda and Clay – a successful, liberal New York couple – are staying in a smart rental summer house in the Hamptons with their kids. When the phone and internet connections go down and a black couple, Ruth and G.H., claiming to be the owners of the house, knock on the door asking for shelter, Amanda and Clay’s proclaimed tolerance is put to the test. Who is this couple? Can they be trusted? And why doesn’t the communications network function? Cyberattack? Terrorism? War? Nuclear accident? Catastrophe looms in Leave the World Behind by Rumaan Alam, the most unsettling and frighteningly believable novel I’ve read in a long time.

In the absence of any information, domestic chores and cooking serve as Valium, calming the nerves while creating the illusion of normality. Things are anything but. An unusually large herd of deer walks past, two pink flamingoes land in the pool. (Escaped from a zoo?) The streets are deserted. And that’s just the beginning.

Alam uses the narrative angle to great effect in this book. We start out seeing the world from Clay and Amanda’s perspective. Some way into the book Ruth’s voice enters abruptly and, a bit later, an omniscient voice which reports disturbing events happening elsewhere, information that never reaches our protagonists. It’s surprising what an unsettling effect it has on the story.

Alam’s triumph is in creating an almost intolerable suspense while telling us very little. Our dependence on technology is laid bare as are the many possible reasons for a disaster. Alam perfectly distills contemporary angst. I wish his editor had weeded out some of the writing that doesn’t work (including a cringing description of sex), apart from that, this book was eerily good. It will haunt me for months to come.

Leave the World Behind by Rumaan Alam is published by Bloomsbury Publishing, 256 pages.