We do not attempt in these two lectures to develop a coherent formalism of nuclear muon-capture, nor do we drive for completeness in the description of what the study of these processes may teach us about the basic interaction or the nuclear structure. The formalism may be consulted in ref. 1 (impulse approximation) or ref. 2 (elementary particle approach). Information on the basic interaction was reviewed in ref. 3 and 4, the nuclear structure aspects being covered in refs. 3, 4 and 5. Some of the topics will be also taken up in the lectures of Professor Primakoff.