I used the opportunity of this edition to correct some minor mistakes and clarify, wherever it possible, exposition of the theory in comparison with the previous edition of this book (Kluwer, Dordrechtet cet, 2000). It provokes - largement of the book, though I tried to present the modern theory of thermic motion of long macromolecules in compact form. I have tried to accumulate the common heritage and to take into account di?erent approaches in the theory of dynamics of linear polymers, at least, to understand and make clear the importance of various ideas for explanation of relaxation phenomena in linear polymers, to present recent development in the ?eld. The theory of non-equilibrium phenomena in polymer systems is based on the fundamental principles of statistical physics. However, the peculiarities of thestructureandthebehaviourofthesystemsnecessitatetheimplementation of special methods and heuristic models that are di?erent from those for gases and solids, so that polymer dynamics has appeared to be a special branch of physicsnow. Themonographcontainsdiscussionsofthemainprinciplesofthe theoryof slowrelaxationphenomena in linearpolymers, elaborated inthe last decades. The basic model of a macromolecule, which allows us a consistent explanation of di?erent relaxation phenomena (di?usion, neutron scattering, viscoelasticity, optical birefringence), remains to be a coarse-grained or be- spring model, considered in di?erent environments: viscous, to describe the behaviourofdilutesolutions,orviscoelastic,todescribethebehaviourofboth weakly and strongly entangled systems.