Publisher Summary Precipitation is a widely used industrial process. It is also a very popular laboratory technique, especially in analytical chemistry, and the literature on this aspect of the subject is voluminous. Precipitation plays an important role not only in chemistry but also in metallurgy, geology, physiology, and other sciences. In the industrial field, the manufacture of photographic chemicals, pharmaceuticals, paints and pigments, polymers, and plastics utilizes the principles of precipitation. For the production of ultrafine powders, precipitation may be considered a useful alternative to conventional crystallization, followed by milling. The term “precipitation” very often refers to nothing more than fast crystallization, although sometimes it also implies an irreversible process—for example, many precipitates are virtually insoluble substances produced by a chemical reaction, whereas the products of most conventional crystallization processes can usually be redissolved if the original conditions of temperature and solution concentration are restored.