The monograph presents data on the structure and properties of membrane-active crown ethers exhibiting complexon, ionophore and channel forming properties. On flat bimolecular and multilamellar layers, crown ethers differing in the mechanisms of membrane action were studied. Significant differences were found in the interaction of complexon, ionophore, and channel forming crown ethers with multilamellar layers. The basic principles of the organization and functioning of two types of ion channels, induced by crown ethers on bilayers, are considered. Ionophore and channel-forming properties of crown ethers were studied, and biological interactions were described along with the possibilities of their practical use. The monograph is designed for biologists, chemists, physicists working at the intersection of sciences, as well as bachelors, masters and teachers of relevant specialties.