In this book, we have studied the geometrical aspects of the space-time with regard to the space of constant curvature, symmetric space and recurrent space, constructed the spherically symmetric homogeneous cosmological model in Einstein's theory of gravitation and the space-time is designed as degenerate vacuum universe when c = 0, the problem of spherically symmetric homogenous space time with perfect fluid and viscous fluid distribution are considered separately in Einstein's theory, the inhomogeneous plane symmetric space-time in presence of macro matter field representing perfect fluid...