Everybody lies, to friends, lovers, doctors, pollsters – and to themselves. In Internet searches, however, people confess their secrets – about sexless marriages, mental health problems, even racist views. Seth Stephens-Davidowitz, an economist and former Google data scientist, shows that this could just be the most important dataset ever collected. This huge database of secrets – unprecedented in human history – offers astonishing, even revolutionary, insights into humankind. Anxiety, for instance, does not increase after a terrorist attack. Crime levels drop when a violent film is released. And racist searches are no higher in Republican areas than in Democrat ones. Time and time again, data shows that the world works in precisely the opposite way to what we would expect.