The developments of Dirac, Heisenberg, Schrödinger and others quickly laid the groundwork of modern quantum theory. A number of significant developments have added to the story since then, such as Quantum Electrodynamics (QED) and Quantum Chromodynamics (QCD), but for most of the work of most chemists and physicists, a working knowledge of the theories of the more rudimentary work mentioned here is more than sufficient. With it, we can understand chemical processes, spectroscopic features, and physical properties. And this is adequate for our work. Go back and start following the links that explain these theories more thoroughly.