This book describes the subject of electrodynamics at classical as well as quantum level, developed as an interaction at a distance. Thus it has electric charges interacting with one another directly and not through the medium of a field. In general such an interaction travels forward and backward in time symmetrically, thus apparently violating the principle of causality. It turns out, however, that in such a description the cosmological boundary conditions become very important. The theory therefore works only in a cosmology with the right boundary conditions; but when it does work it is free from the divergences that plague a quantum field theory.

Contents:

• Classical Electrodynamics: Historical Background
• The Problems of Classical Field Theory
• The Wheeler-Feynman Absorber Theory of Radiation
• Action at a Distance in Curved Spacetime
• Cosmological Models
• Response of the Expanding Universe
• Quantum Electrodynamics Non-Relativistic Processes: The Path-Integral Approach to Quantum Mechanics
• Perturbation Theory and the Influence Functional
• Absorption and Stimulated Emission
• Spontaneous Emission
• The Complete Influence Functional and the Level Shift Formula
• Relativistic Quantum Electrodynamics: Path Integrals for Relativisitc Particles
• Many Particle Interactions and the Quantum Response of the Universe
• Self Action
• Cosmological Cut-Offs to Radiative Corrections
• Concluding Remarks