The aim of this study was to have an insight into the sulfide mineralogy, mainly based on sulfides mineralogical studies prior to the year 1975. In the first two chapters, the metal sulfides crystal structures and chemistries are reviewed. Then, the electronic interactions and chemical bonding followed by experimental methods in sulfides research with the proposed phase equilibria are reviewed. Phase relations in the (Cu, Ni, Zn)-S systems are discussed. Due to its influential and common appearance, in most natural sulfides (the common rock-forming minerals: po and py), the Fe-S system has been summarized relatively in detail. Sulfide petrology has been also discussed. The metal sulfides are the raw materials for most of the world supplies of non-ferrous metals. Their complex chemistry, as a result of high impurities association (such as As, Sb, Bi, etc...) and less base-metals content (metal poor rocks: composition of base-metal is less than 1 at.%), and the ever growing demand for the metals as well as the embroiling need to optimize minerals processing and sulfides smelting claim intense mineralogical studies. The main goal of such studies are to acquire accurate thermodynamic data which are useful to predict reactions and stable relationships, and in defining the limiting conditions under which phases may exist.Peer reviewe