Summary: "The Universe" by P.L. Bhatnagar explores the vast dimensions of the universe through a series of lectures sponsored by the University Grants Commission. It covers topics such as observational astronomy, galaxies, radio astronomy, stellar constellations, and more. The book delves into the evolution of cosmological theories, including the Steady State Theory and the Evolutionary Theory, to explain the origin and structure of the universe. It also discusses the methods used to measure distances, masses, and luminosities of celestial bodies, such as parallax and spectroscopic analysis. With a focus on visual and spectroscopic binaries, white dwarfs, and other stellar phenomena, the book provides a comprehensive insight into the mysteries of the universe and the tools astronomers use to study it.