Аннотация:Nanogels can be called the new old§ objects of polymerchemistry. New because we have formulated the criteria for theassignment of objects to this group within the macromoleculeparticleconcept and developed the methods for their directed andcontrolled synthesis. Old because the application of these criteriato the earlier known systems allows us to surely classify them asnanogels. It is shown that this classification per se providesinsight into the organization of their molecular structures andenables directed modification. This means a transition from theempirical control of the properties to molecular design. Thecurrent review presents a brief historical overview of denselycross-linked nanogels and their main synthetic routes andhighlights the principles and approaches to the control of theirstructures and molecular-mass characteristics, application scope,and prospects for further development.