chapter 1 Foundations of gamma-ray astronomy -- chapter 2 Very high energy gamma-ray detectors -- chapter 3 High energy gamma-ray telescopes in space -- chapter 4 Galactic plane -- chapter 5 Supernovae and supernova remnants -- chapter 6 Gamma-ray observations of the Crab Nebula -- chapter 7 Gamma-ray observations of supernova remnants -- chapter 8 Gamma-ray pulsars and binaries -- chapter 9 Unidentified sources -- chapter 10 Extragalactic sources -- chapter 11 Active galactic nuclei: observations -- chapter 12 Active galactic nuclei: models -- chapter 13 Gamma-ray bursts -- chapter 14 Diffuse background radiation.