POTLIB is an online library of global and semiglobal potential energy surface subprograms for calculating Born-Oppenheimer energies as a function of nuclear geometry. The library currently features more than 250 potential energy routines for a wide range of chemical systems. Our goal is to facilitate chemical dynamics research by collecting and disseminating a comprehensive collection of state-of-the-art potential energy routines (developed by a wide, international group of researchers) with systematic and well-defined interfaces for use with chemical dynamics programs.