Pion, muon decays and weak interaction symmetries

We review the recent measurements of the rare pion decays: π+→π0e+ν (beta, πe3, or πβ decay), radiative decay π+→e+νγ (πe2γ or RPD), and π+→e+ν (πe2), as well as the radiative muon decay, , their theoretical implications, and prospects for further improvement.