Cellulose ethers are water-soluble polymers derived from cellulose, the most abundant polymer in nature. For a long time these versatile products have played an important role in foods, cosmetics, pharmaceuticals, latex paints, construction products, ceramics, and a host of other applications. Cellulose products are used as thickeners, binders, film formers, and water-retention agents. They also function as suspension aids, surfactants, lubricants, protective colloids, and emulsifiers. In addition, solutions of cellulose thermally gel, a unique property that plays a key role in a surprising variety of applications.