This project is concerned with the development of a general purpose software and of its supporting mathematical results for Sturm-Liouville problems. An algorithm that incorporates the resulting mathematical theory to the maximum extent possible will be developed and implemented in the code SPDNSF. This class of Sturm-Liouville problems has many applications in science and engineering, particularly, in quantum physics, in quantum chemistry, in transport theory, in acoustics, in geophysical applications, and in vibration and heat flow problems in engineering. Upon completion, the code will be made available to researchers in science and engineering.