The book includes a thorough description of a wide range of physical properties of organic superconductors of reduced dimensionality. The authors start with an overview of the field followed by a background discussion and selected experimental topics. A critical discussion of theoretical proposals is presented under the constraints of experimental observations and exciting possibilities for the symmetry of the order parameter are presented, including the cases of inhomogeneous superconducting states and triplet superconductivity. The possible origins of Cooper pairing are explored and tests to detect experimentally the pairing symmetry are described in detail. The book ends with a discussion of important open questions, where the search for their answers will keep the field alive for the next decade.