The physics of weak interactions

The authors give a general outlook on the weak interactions theory, the trends of recent developments and their implications. The main results obtained at Scalay in the study of K decays both with counters and bubble chamber techniques, are presented and compared with theoretical predictions. The new possibilities in neutrino physics opened by the 400 GeV accelerator in construction at CERN are presented. The experiments proposed by the DPhPE in collaboration with other European laboratories are described. (6 refs).