In this groundbreaking work, Seth Stephens-Davidowitz, a Harvard-trained economist, former Google data scientist, and New York Times writer, argues that much of what we thought about people has been dead wrong. The reason? People lie, to friends, lovers, doctors, surveys--and themselves. However, we no longer need to rely on what people tell us. New data from the internet--the traces of information that billions of people leave on Google, social media, dating, and even pornography sites--finally reveals the truth.