In the monograph, recognition of the receptors by drugs is described as a complex phenomenon that has not been yet entirely understood. The description of molecular structure information necessary to achieve specific receptors without getting lost among huge amounts of non-specific acceptors is present. Various examples of receptor' binding features for narcotic analgetics, neuroleptics, tranquilisators, ligands of acetylcholine receptors. The three stages of drug interaction with acceptors are considered, namely, distant stage, stage of orientation of the molecule on the acceptor, stage of molecule fixation. Kinetics and thermodynamics of these stages as well as factors preventing drug binding to non-specific acceptors are described. Some considerations concerning methods of changing activity and selectivity of drugs are given. Literature information needed for analysis of molecular mechanisms of interactions between drugs and receptors is present.