It is the saturation of the transition temperature T-c in the range of 24 K for known materials in the late sixties that triggered the search for additional materials offering new coupling mechanisms leading in turn to higher T-c's. As a result of this stimulation, superconductivity in organic matter was discovered in tetramethyl-tetraselenafulvalene-hexafluorophosphate, (TMTSF)(2)PF6, in 1979, in the laboratory founded at Orsay by Professor Friedel and his colleagues in 1962. Although this conductor is a prototype example for low-dimensional physics, we mostly focus in this article on the superconducting phase of the ambient-pressure superconductor (TMTSF)(2)ClO4, which has been studied most intensively among the TMTSF salts. We shall present a series of experimental results supporting nodal d-wave symmetry for the superconducting gap in these prototypical quasi-one-dimensional conductors. (C) 2015 Academie des sciences. Published by Elsevier Masson SAS.