In the Wall Street Journal, Daniel Levitin likes it a lot!

A very different—indeed startling—vision of the future .. What is remarkable about Mr. Hanson’s book is not just the detail with which he imagines this future but the way he situates it within a perceptive analysis of our human past and present. .. His is a dyspeptic-topia. It looks grim. ..

Mr. Hanson’s book is comprehensive and not put-downable. The author has thought of everything. He’s anticipated every one of my objections, including the manifestly unscientific one of how creepy this all sounds. He admirably explains the assumptions he’s making and the limitations. ..

The only weak point I find in the argument is that it seems to me that if we were as close to emulating human brains as we would need to be for Mr. Hanson’s predictions to come true, you’d think that by now we’d already have emulated ant brains, or Venus fly traps or even tree bark. ..

For my own part, I hope that the ems come soon. .. Even if you aren’t interested in the future, “The Age of Em” provides a wonderful overview of the current social psychology of productivity. .. For readers of this newspaper, a particularly interesting section discusses how free-market forces will change economic behaviors, negotiations, price-setting and fee structures. Mr. Hanson is an amiable narrator and guide to all these topics and more. We could use a few more of him.