Compton effect as a basic process in the conversion region

In this small review, the following general properties of the Compton scattering as the basic process for creating γγ colliders in the scheme suggested in Ginzburg et al. (Inst. Nucl. Phys. 34 (1981) 514; Nucl. Instr. and Meth. 205 (1983) 47) are considered: kinematics, photon spectrum, angular distribution, polarization of the final photons and electrons as well as some related problems.