This is the 2nd edition of a highly successful title on this fascinating and complex subject. Concentrating primarily on the theory behind the origin and the evolution of the universe, and where appropriate relating it to observation, the new features of the this addition include: An overall introduction to the bookTwo new chapters: Gravitational Lensing and Gravitational WavesEach part has a collection of exercises with solutions to numerical parts at the end of the bookContains a table of physical constantsThe addition of a consolidated bibilography