Recent impressive improvements in the application of Quantum Mechanics, coupled with a significant increase in both speed and storage capabilities of modern computers, allow to depict the energy and reactive properties of chemically complex materials through first principles and to discard the dogmatic assumption that Natural Complexity cannot be reproduced by a strict application of theory. In the following I will try to convey methods and procedures aimed at obtaining sound thermodynamic and thermo-physical data for Earth's materials under various aggregation states. In doing this I will partly use my own production as reference and I will have to introduce concepts that may appear obvious or even obsolete to experienced readers. My prearranged apologies. The emphasis will focus on the practical aspects of the various procedures, with a few hints on the underlying concepts.