A classification of common solvents according to their dipolarity and hydrogen-bonding acidity and basicity has been developed, based on the Kamlet-Taft solvatochromic parameter scheme. This approach has been compared with the Snyder-Rohrschneider solvent-selectivity triangle (SST). The two solvent-classification schemes are found to be generally similar. Both SST-based schemes are also compared to an analysis of solvent selectivity based on linear salvation energy relationships. While there are considerable similarities, important practical differences, especially in the case of reversed-phase liquid chromatography, are evident.