New York Times tech reporter Kashmir Hill was skeptical when she got a tip about a mysterious app called Clearview AI that claimed it could, with 99 percent accuracy, identify anyone based on just one snapshot of their face. The company was boosted by a cast of controversial characters, including billionaire Donald Trump backer Peter Thiel and conservative provocateur Charles C. Johnson, all of whom seemed eager to release this society-altering technology on the public.This is a gripping true story about the rise of a technological superpower and an urgent warning that, in the absence of vigilance and government regulation, facial recognition is one of many new technologies that challenge what Supreme Court Justice Louis Brandeis once called "the right to be left alone."