The use of computers to investigate the electronic structure of atoms, molecules, and solids, initiated by pioneering research groups as mentioned above, penetrated, rather slowly around 1960, into theoretical chemistry. In 1989, Enrico Clementi launched the Modern Techniques in Computational Chemistry initiative advocating a global simulation methodology. Having been around on a small scale in the 1970s, the development and use of these single-chip devices took off explosively in the 1980s by the unbelievably successful introduction of the personal computer. The idea of having an exchange of quantum chemistry programs among the various groups who were active in quantum chemistry has arisen, as early as 1962. A successful endeavor considering the fact that data communication was still in its infancy. Simultaneously, there was a growing demand for smaller and cheaper machines or minis that could be used locally. The adaptation of such complex packages to novel massively parallel computer architectures requires team efforts that are far from trivial.