Direct detection of gravitational waves from astrophysical sources is one of the great challenges of contemporary experimental physics. Observing gravitational waves gives unique information on compact cosmic objects (black holes and neutron stars) and gravitational physics at extreme conditions. Also, gravitational waves allow in principle the investigation of processes in the very early universe which are not observable by means of electromagnetic, cosmic ray or neutrino signals.
The status of this field of research will be reviewed, with particular reference to the presently operating detectors, and perspectives with earth based and space detectors will be reported.