This expanded second edition of Relativity and the Nature of Spacetime c- tains several major changes and a number of additions to different ch- ters. Two chapters (Chaps. 6 and 7), which discussed two speci?c groups of arguments against the reality of spacetime, have been transformed into - pendices (A and B). Two new chapters (Chaps. 6 and 10) have been added. Chapter 6, entitled Why Is the Issue of the Nature of Spacetime So Imp- tant?, elaborates on what was Sect. 5. 6 of the ?rst edition, and addresses some recent work on the nature of spacetime ¿ for example, the growing (or evolving) block universe model of the world, which has recently been - vived by several physicists as what appears to be the last remaining alter- tive to the Minkowski absolute four-dimensional world (after it had become an undeniable fact that three-dimensionalism, or presentism, contradicts the relativistic experimental evidence). Chapter 10, entitled Spacetime and the Nature of Quantum Objects and based on what used to be Sects. 6. 2 and 6. 3 in the ?rst edition, explores the implications of the issue of the nature of spacetime for quantum physics, in order to see whether it can provide some insight into the nature of quantum objects. Two new sections have been included, namely, Sect. 5. 6 entitled Re- tivization of Existence and Observers in General Relativity and Sect. 7. 6 - titled Probing the Anisotropic Velocity of Light by a Terrestrial Experiment.