Recently there has been a significant increase in the share of polyurethane varnish-and-paint materials in the total amount of varnish-and-paint materials produced in this country and abroad. Polyurethane coatings are used for protection of metal, concrete, reinforced concrete, and wood; as well as in production of non-woven, doubled and combined fabrics for various purposes, in particular for footwear, clothing, technical fabrics and other articles. A characteristic feature of polyurethane coatings is also that they are used not only to produce coatings on traditional rigid supports but also on flexible porous supports. This book presents and reviews research on the structure and properties of modified polyurethanes.