The emphasis of this book is on new advances in polymer gels, particularly with biomedical applications in mind. At the same time, current progress in synthesis, characterization, and physicochemical characterization and properties are highlighted. Section I deals with the fundamentals of the static and dynamic properties of polymer networks and gels. Section II is devoted to the applications of gels to medicine and biology, particularly the use of the gel medium for controlled drug delivery and encapsulation of proteins and enzymes. Section III covers the synthesis and characterization of novel polymeric networks and gels such as hydrogels, cyanogels, and gels of amphiphilic block copolymers. Section IV discusses visco-elastic properties of gels and cross-linked networks, interactions between physical and chemical gels, gel formation and interactions with vesicles, and photo-responsive rheological behavior.