In volume III/21 a compilation is given of all reported experimental data on superconducting materials from the discovery of this phenomenon. The presented data include not only the superconducting properties related to a given material, but also the full metallurgical and crystallographical characterization. In addition to other low temperature physical properties, which are explicitly given in a particular column are presented. The substances are arranged alphabetically by the base element, i.e. that element with the highest concentration in an alloy or compound. Only original and critically reviewed experimental data are retained.