Abstract Gamma-rays are located in the hard electromagnetic wave band. The range of measured energies is restricted to the interval between about 105 eV and 1016 eV (the latter is the highest energy of detected particles which are supposed to be gamma-ray photons). Gamma-ray astronomy is relatively young—approximately 25 years old. So only a few space experiments have been performed in this energy range. New perspectives opened since the launch of the Gamma-Ray Observatory will provide the basis for experiments over the coming years. In this paper the problems and achievements of gamma-ray astronomy are described.