Thisisthesecondeditionofabookonthephenomenological foundations ofmodern cosmology. The ?rst edition was surprisingly well timed. In the preceding 3 years, advances in astronomy had laid the foundations of the dark-energy/dark-matter c- mological model. In 1998, observations of type Ia supernova by the Supernova C- mology Project and High Z team suggested that the expansion of the universe is accelerating. In 2000, Boomerang and Maxima observed clearly...