The condensed phases of helium three provide an exciting laboratory for many fundamental questions in condensed matter physics. Due to its light mass and weak interatomic potential, the condensed phases of helium display quantum effects more dramatically than any other atomic system. Intuition based on classical experience is often misleading in these phases: the solid phase for instance is less ordered at low temperature than the liquid phase. The present book is unique in covering all the low temperature properties of helium three as liquid, superfluid, and solid. It provides an introduction to the extensive literature on helium three from the point of view of an experimentalist, and includes the analogy of its properties with the cosmological 'big bang'. Graduate students, researchers, and professionals in condensed matter physics and low temperature physics will find this the standard reference work for the decade to come.