[en] This is an introductory paper to theoretical and experimental gravitational wave research. In the first part, we give the precise mathematical description of a weak gravitational wave in the general framework of metric theories. Then we discuss the effect of these waves on material systems and the principle of the present detectors. The third part concerns the generation of gravitational radiations and reviews the possible astrophysical sources. Finally, we discuss the limitations and the state of the art of present detectors