Astronomers have successfully observed a great deal of the Universe's history, from recording the afterglow of the Big Bang to imaging thousands of galaxies, and even to visualising an actual black hole. There's a lot for astronomers to be smug about. But when it comes to understanding how the Universe began and grew up we are literally in the dark ages. In effect, we are missing the first one billion years from the timeline of the Universe. This brief but far-reaching period in the Universe's history, known to astrophysicists as the 'Epoch of Reionisation', represents the start of the cosmos as we experience it today. The time when the very first stars burst into life, when darkness gave way to light. After hundreds of millions of years of dark, uneventful expansion, one by the one these stars suddenly came into being. This was the point at which the chaos of the Big Bang first began to yield to the order of galaxies, black holes and stars, kick-starting the pathway to planets, to comets, to moons, and to life itself. Incorporating the very latest research into this branch of astrophysics, this book sheds light on this time of darkness, telling the story of these first stars, hundreds of times the size of the Sun and a million times brighter, lonely giants that lived fast and died young in powerful explosions that seeded the Universe with the heavy elements that we are made of. Emma Chapman tells us how these stars formed, why they were so unusual, and what they can teach us about the Universe today. She also offers a first-hand look at the immense telescopes about to come on line to peer into the past, searching for the echoes and footprints of these stars, to take this period in the Universe's history from the realm of theoretical physics towards the wonder of observational astronomy.