An introduction to channeling and channeling (Kumakhov) radiation is given. Relativistic and quantum-mechanical effects are discussed in function of the electron or positron energy. Phenomena of Quantum Electrodynamics in strong macroscopic field, which can be tested in channeling conditions, are described. Recipees for semi-classical Monte-Carlo simulations are presented and one of them compared with experiments at 10 and 150 GeV.