Roger McNamee Has Gone From Mentoring Facebook CEO Mark Zuckerberg to Sounding the Alarm

Once a Facebook booster and early advisor to CEO Mark Zuckerberg, well-known tech investor Roger McNamee has changed his tune. Facebook is, in fact, a privacy train wreck, he says, and its leader appears to care more about growth than user privacy.

McNamee is so worried that he wrote a book, Zucked: Waking Up to the Facebook Catastrophe, that debuts on Tuesday. In the book, he details a laundry list of concerns about big tech companies like Facebook and Google, following their many data and privacy scandals and for what McNamee calls their failure to own up to their problems.

McNamee, who has left investing but still owns Facebook shares, says he began his book as a research project in 2016 and then later partnered on it with Tristan Harris, a former Google employee who taught McNamee about how companies leverage psychology to increase use of their technologies. A year later, McNamee was so worked up that he turned from a mere researcher into an activist against the data collection and persuasive techniques that tech companies employ to get people to use their products.

“The problem today is that … the people are not the customers; the people are the fuel,” McNamee said. “We are just a metric. We’re not in any way something they [technology companies] view as human, and that is a huge issue.”

Now McNamee is trying to sound the alarm to as many people as possible about how Facebook and its tech brethren operate—and how consumers can protect themselves.

McNamee talked to Fortune about why he wrote the book and about his experience with Facebook. The responses have been edited for length and clarity:

Fortune: Why write a book now, given your history with Facebook?

McNamee: I’m just a cheerleader, and then all of a sudden in 2016, I started to see things that simply didn’t fit my preconceived notion of the company.

I reached out to Mark and Sheryl [Sandberg, Facebook’s chief operating officer] and said, “Guys, there’s something really wrong here.” What I didn’t realize was how much the culture was a part of that. I was hoping they would take it seriously enough to do internal investigation.

Facebook’s leadership wasn’t interested.

I started researching and met Tristan Harris. When I met him, it was like, “Oh my god.” He’s explaining how Internet platforms use psychology to pray on the weakest aspects of human mind to play on habits and addictions. That’s why the presidential election could be swung, and that’s why the “leave” campaign in Brexit was so much more effective than remain campaign.

The goal was to try to persuade people at Facebook and Google that there was a problem here, and they should fix it. I think it’s safe to say we were unsuccessful in that mission.