This book is about the study of manifolds with indefinite metrics. Since the concept of space-time in physics is endowed with indefinite metric and by combining space and time into a single manifold, various theories have been simplified, so the study of manifolds with indefinite metric has a great relevance towards the geometrization of Physics. In this context, various manifolds namely quasi-Kaehler manifolds, Kaehler manifolds and Sasakian manifolds, with indefinite metric, have been studied in this book. It also elaborates the concept of lightlike (degenerate) geometry of submanifolds. In...