New fields of science and technology call for new materials with valuable performance characteristics. Long-term resistance to such temperatures can be found only in polymers with chains made up of thermostable fragments. Particularly interesting in this respect are elementorganic polymers with inorganic and organo-inorganic molecular chains. Elementorganic polymers are not only highly thermostable, but also perform well under low temperatures, sunlight, humidity, weather, etc. Thus, these polymers (especially silicones) are widely and effectively used in the electrical, radio, coal, mechanical rubber, aircraft, metallurgical, textile and other industries. They are of great utility not only in industry, but also in households and in medicine, where their merits can hardly be overestimated. The need to publish this book arose with the scientific and technical developments of the last decade, the reconstruction and technical renovation of existing factories, as well as fundamental changes in some syntheses of elementorganic monomers and polymers. Moreover, nowadays it is essential to train highly-skilled chemical engineers with a comprehensive knowledge of current chemistry, of the production technology of elementorganic monomers and polymers, and of their characteristics and applications.