Triboluminescence is the emission of light caused by the application of mechanical energy to solids. Although the phenomenon has been known since the 17th century, neither the excited state origins of the luminescence nor the mechanism by which it is excited were understood until recently. Our efforts have focussed on the fundamental requirements for triboluminescence. We have uncovered and studied the fracture requirement, the pressure requirement, and the structure requirement for triboluminescence activity. We have also derived a quantitative theory for the dynamics of triboluminescence based on the dynamics of the creation and interaction of mobile fractures in a crystal. In addition to explaining the time dependence of the luminescence, the theory treats the effects of size ad impact velocity on the luminescence intensity. The instrument--which was designed to measure these effects--also enabled us to quantitively compare the relative intensities of various crystals. We have continued to study triboluminescence spectroscopy. High pressure spectroscopy has played an important role in investigating the pressure requirements for triboluminescence. Finally, the synthesis and chemistry of triboluminescent materials, which have continued to be a cornerstone in the above investigations, led to the discovery of the polymorphic hexaphenylcarbodiphosphorane crystals and to other interesting materials which are described.