A friend of mine says that whenever he walks into someone’s home he’s tempted to yell out, “Hey, Alexa,” or “O.K., Google,” and order 50 pizzas, just to see if there’s a device listening in on whatever gossip he planned to dish out next.

Shoshana Zuboff would undoubtedly get the joke, but she probably wouldn’t laugh. In “The Age of Surveillance Capitalism,” she warns against mistaking the soothing voice of a personal digital assistant for “anything other than the exploitation of your needs.” The cliché that “if you’re not paying for it, you’re the product” isn’t alarming enough for her. She likens the big tech platforms to elephant poachers, and our personal data to ivory tusks. “You are not the product,” she says. “You are the abandoned carcass.”

O.K., Zuboff, tell me more. It’s a testament to how extraordinarily intelligent her book is that by the time I was compared to an elephant carcass, I resisted the urge to toss it across the room. Zuboff, a professor emerita of Harvard Business School and the author of “In the Age of the Smart Machine” (1988), has a dramatic streak that could come off as simply grandiose if she didn’t so painstakingly make her case. She says we’re living through such “a bold and unprecedented shift in capitalist methods” that even as we encounter the occasional story about Facebook allowing its corporate clients to read users’ private messages or the software in Google’s Street View cars scraping unencrypted information from people’s homes, the American public doesn’t yet grasp the new dispensation in its entirety.

So many people take care to calibrate their privacy settings just so, sharing certain things with friends and keeping other things hidden, while their data still gets collected and shared among apps for possible monetization now or later. Google and Facebook might not call to mind the belching smoke stacks and child laborers of the Industrial Revolution, but Zuboff argues that they’re run by people who have turned out to be just as ruthless and profit-seeking as any Gilded Age tycoon. Instead of mining the natural landscape, surveillance capitalists extract their raw material from human experience.