  High energy gamma-ray astronomy has recently made significant progresss
through ground-based instruments like the {\it H.E.S.S.} array of imaging
atmospheric Cherenkov telescopes. The unprecedented angular resolution and the
large field of view has allowed to spatially resolve for the first time the
morphology of gamma-ray sources in the TeV energy range. The experimental
technique is described and the types of sources detected and still expected are
discussed. Selected results include objects as different as a Galactic binary
Pulsar, the Galactic Center and Supernova Remnants but they also concern the
diffuse extragalactic optical/infrared radiation field. Finally, a scan of the
Galactic plane in TeV gamma rays is described which has led to a significant
number of new TeV sources, many of which are still unidentified in other
wavelengths. The field has a close connection with X-ray astronomy which allows
the study of the synchrotron emission from these very high energy sources.
