The cold universe is the part of the universe in a cold form close to the background radiation temperature. Until recently, this cold state has been neglected because it is hard to observe, although it must inevitably play a crucial role as the original state of most of the hotter observable objects such as planets, stars, and galaxies. Fortunately, the cold universe currently becomes more and more accessible with newer instruments. This book contains the printed version of the lectures given at the 32nd Saas-Fee Advanced Course "The Cold Universe" by three eminent scientists in the field: Andrew Blain, Francoise Combes and Bruce Draine. Cold objects at cosmological distances, the origin of galaxies, the role of molecules in galaxies, and the physics of the dust in cold clouds are the main topics treated. This book contains an accessible and up-to-date review of the field and should be useful for many years to astronomy students, cosmologists, physicists and researchers.