"The Fourth Age," Byron Reese, Atria, 320 pages, $27.

“The Fourth Age: Smart Robots, Conscious Computers and the Future of Humanity” discusses what the rise of artificial intelligence will mean for us — and also forces readers to challenge their preconceptions. And it manages to do all this in a way that is both entertaining and engaging.

Byron Reese, whose day job is CEO of the technology research company Gigaom, begins by grounding the reader in what he sees as the three major changes in human civilization. The discovery of fire and language led humans to greatly increase their brain size, paving the way for future advancement. Then the development of agriculture led to the birth of cities. Finally, writing and the wheel have shaped much of everything until the present.

Robots and A.I., meanwhile, promise a fourth age characterized by new challenges, including what the place of humans will be in a world filled with devices that are stronger and potentially smarter than us.

Reese makes the possibility of impending doom quite palpable. It’s not a light read, in large part because the issues Reese is grappling with are complicated and filled with ethical problems the likes of which humans have never confronted. Will robots and A.I. take all the jobs? Will all of society benefit, or only those who own the robots? Assuming we could, should we build computers that are as broadly intelligent as humans? Can computers become conscious?

You don’t have to have all the answers — even the experts don’t agree. But “The Fourth Age” successfully forces us to face just how thorny those questions are.