This book is a collection of the varied aspects of polysaccharides in microorganisms, plants and animals. The diversity of these polysaccharides emerges from the structural alterations and the monosaccharide content which is under genetic control. Their physical as well as chemical properties have made them useful in a variety of food, pharmaceutical and industrial applications. These properties determine their biological activity and their functions in different applications. The use of polysaccharides as therapeutics, the role played by them in protection and preservation of food, as carriers of drugs, nutrients and their ability to communicate with molecules for improving textures of food colloids, as well as for efficient delivery are a few important functions. The book is organized under two sections: Applications in Food Industry and Applications in Pharmaceutical Industry.