Why does anything exist? Is the void the same as nothingness? Until recently, such questions were asked only by metaphysicians and theologians. The time has come for science to restate them, while examining the true nature of reality. Michel Cassé shows that each cubic centimetre of space is filled with an amazing universe of virtual electron-positon pairs and a myriad of different types of quanta, including photons, gluons, and W and Z particles. Neutral but inhabited, the void lies at the heart of matter. Why should anyone be surprised that a world came into existence out of the void?