A spellbinding novel set in the universe of Isaac Asimov's classic Galactic Empire series and Foundation series. Due to circumstances within our control ... tomorrow will be canceled. The Eternals, the ruling class of the Future, had the power of life and death not only over every human being but over the very centuries into which they were born. Past, Present, and Future could be created or destroyed at will. You had to be special to become an Eternal. Andrew Harlan was special. Until he committed the one unforgivable sin -- falling in love. Eternals weren't supposed to have feelings. But Andrew could not deny the sensations that were struggling within him. He knew he could not keep this secret forever. And so he began to plan his escape, a plan that changed his own past ... and threatened Eternity itself.

In this book, Robert Wald provides a coherent, pedagogical introduction to the formulation of quantum field theory in curved spacetime. He begins with a treatment of the ordinary one-dimensional quantum harmonic oscillator, progresses through the construction of quantum field theory in flat spacetime to possible constructions of quantum field theory in curved spacetime, and, ultimately, to an algebraic formulation of the theory. In his presentation, Wald disentangles essential features of the theory from inessential ones (such as a particle interpretation) and clarifies relationships between various approaches to the formulation of the theory. He also provides a comprehensive, up-to-date account of the Unruh effect, the Hawking effect, and some of its ramifications. In particular, the subject of black hole thermodynamics, which remains an active area of research, is treated in depth. This book will be accessible to students and researchers who have had introductory courses in general relativity and quantum field theory, and will be of interest to scientists in general relativity and related fields.