Recent results, the present status and the perspectives of high energy
gamma-ray astronomy are described. Since the satellite observations by the
Compton Gamma Ray Observatory and its precursor missions have been reviewed
extensively, emphasis is on the results from the ground-based gamma-ray
telescopes. They concern the physics of Pulsar Nebulae, Supernova Remnants in
their assumed role as the Galactic sources of Cosmic Rays, Jets from Active
Galactic Nuclei, and the Extragalactic Background radiation field due to stars
and dust in galaxies. Since the gamma-ray emission is nonthermal, this kind of
astronomy deals with the pervasive high-energy nonequilibrium states in the
Universe. The present build-up of larger and more sensitive instruments, both
on the ground and in space, gives fascinating prospects also for observational
cosmology and astroparticle physics. Through realistically possible further
observational developments at high mountain altitudes a rapid extension of the
field is to be expected.Comment: 23 pages, 11 figures. To appear in "Astronomy, Cosmology and
Fundamental Physics", ed. P. A. Shaver, L. Di Lella, and A. Gimenez, Proc.
ESA-CERN-ESO Symposium, Garching, March 2002. Springer-Verlag, Berlin,
Heidelberg, series "ESO Astrophysics Symposia
