General relativity is the theory of gravitation which provides a complete description of gravity as a geometric property of space and time. The understanding of how matter and radiation warps the geometry of space and time is governed by the Einstein field equations. This theory departs significantly from classical physics especially in relation to the geometry of space, the passage of time, the propagation of light and the motion of bodies in free fall. This is evident in its treatment of gravitational time delay, gravitational time dilation, the gravitational redshift of light and gravitational lensing. The study of the origin and evolution of the universe, starting from the Big Bang to the present and the description of its ultimate fate in the future is under the domain of cosmology. It further studies the large scale dynamics and structures of the universe. There have been significant advances in our understanding of the universe, due to advances in the observations of the microwave background, gravitational lensing and distant supernovae. The detection of gravitational waves in recent times has further strengthened the theories of the Big Bang and cosmic inflation. This book contains some path-breaking studies in the field of cosmology. It provides comprehensive insights into general relativity and its ramifications relative to the understanding of the universe and its dynamics. Scientists and students actively engaged in these areas will find this book full of crucial and unexplored concepts.