Physical processes involving Majorana neutrinos

The Feynman rules for Majorana neutrinos are reviewed and applied. The processes discussed are ${\nu }^{\prime }\to \nu \gamma$, ${\nu }^{\prime }\to \nu e^{+}{e}^{-}$, and neutrino oscillations, especially with regard to the difference between Dirac and Majorana neutrinos. Some special features of CP violation in the neutrino sector are pointed out.