Book excerpt: Most texts on electromagnetic theory follow the classical approach of steady state solutions of Maxwell's equations. In Interstellar Propagation of Electromagnetic Signals, the authors, H. Harmuth and K. Lukin, point out the deficiencies in Maxwell's theory and present an exciting new way of obtaining transient or signals solutions. This book can be used by researchers, graduate students and scientists in the areas of physics, astrophysics, astronomy and electromagnetic theory or electromagnetics.