Gamma-ray astronomy at high energies

Progress in high-energy gamma-ray astronomy has depended upon the development of sophisticated detectors and analysis techniques. Observations in this decade using space-based and ground-based detectors have observed gamma-ray emission from a variety of sources. For the first time a consistent picture of the γ-ray sky has emerged. This article describes the detection techniques in γ-ray astronomy, the nature of the astrophysical objects studied, and the present state of the observations. Several possible new directions in the field are also described.