Gamma-ray astronomy began in the mid-1960s with balloon satellite, and, at very high photon energies, also with ground-based instruments. However, the most significant progress was made in the last decade of the 20th century, when the tree satellite missions SIGMA, Compton, and Beppo-Sax gave a completely new picture of our Universe and made gamma-ray astronomy an integral part of astronomical research. This book, written by well-known experts, gives...