Recent developments in the experimental solid state chemistry, condensed matter physics and material science have offered us new possibilities in controlling synthesis routes, especially by varying the pressure and temperature. Similarly, the development of new theoretical methods and tools makes it worthwhile to reinvestigate apparently well-known systems. In this book, various inorganic binary AB compounds, in particular lead sulfide (PbS) and zinc oxide (ZnO), have been investigated using several different theoretical methods, e.g. Simulated Annealing, Monte Carlo, Data Mining, etc....