Facebook knew it had a problem. The company had been humiliated by headlines, painted as complicit in the election of Trump and in an assault on the global social fabric. Their stated mission was to connect people, but they couldn't afford to destroy society in the process. And so they hired a small team to make sure they didn't repeat the same mistakes.

From the Wall Street Journal reporter whose explosive stories have rocked Facebook and its leadership - and are now spurring international investigations - this is the story of the Civic Integrity Team- a select group of engineers, coders, economists, and experts hired to peer inside the company's secretive algorithms for the first time and find out what exactly was going wrong.

They were successful. Too successful. The Integrity unit discovered proof that Facebook distorted and amplified the basest of human impulses, and was not merely providing a platform for bad actors but amplifying their power. Enduring personal trauma and professional resistance in their often lonely and dark investigations, the Integrity team nevertheless isolated many of Facebook's worst problems, complete with tentative and hopeful steps to solve them - only to discover that they were set up to fail, and would have to take matters into their own hands.