GPS and CSS radio sources

The spectral and kinematic properties of GPS and CSS radio sources and methods for determining theirages are discussed. The data presented here do not support a mechanism of accretion of dust or moleculargas on massive black holes located in the central regions of radio galaxies of these classes as the sourceof their activity. The nature of GPS and CSS objects has not been fully clarified. Further detailed studiesin the optical, radio, and other spectral ranges will be required in order to establish the true nature ofthis class of source.