Kaon and Muon Decay Phenomenology

Theoretical aspects of kaon and muon decays are reviewed. In particular, three topics on kaon and muon decays, namely $K\to \pi \nu \bar{\nu }$ processes, T violation in $K^{+}\to {\pi }^0{\mu }^{+}\nu$ decay and lepton flavor violation in muon decay are considered. Theoretical backgrounds and possible significance on new physics searches by these processes are discussed.