This is the inside story of one of the world's largest particle detectors. Two years ago, the ATLAS detector at the Large Hadron Collider in Geneva began investigating the most powerful particle collisions physicists have ever created. Its discoveries include evidence of a new particle that many think is the famous and long-sought Higgs boson. This book tells the story of one of the world's largest particle detectors, from its inception in the late 1980s to its construction in the 2000s and its first years of operation in the 2010s. You can find out why a machine designed to find tiny subatomic particles exceeds the height of the tallest dinosaurs, why the ATLAS detector throws away 99.998 per cent of the data it finds in the blink of an eye - and why its search for discoveries that will change the way we think about the universe has only just begun.