A state of the art description of organic photo- and electroactive molecules and their practical applications. Topics covered include molecular design and synthesis of highly light sensitive molecules and phenomena associated with electron-photon interaction in organic molecules: nonlinear beam propagation, photorefractivity, multiphoton excitations and absorption, charge photogeneration and mobility, photo- and electroluminescence, photochromism and electrochromism, organic synthesis, material engineering and processing. Applications are addresses: optical data storage, LEDs, optical signalling processing, optical power limiters.