Presenting a systematic and comprehensive account of the original work of the Bogolubov School of Statistical Mechanics, this unique book-containing material previously unavailable in the West-takes the reader step by step from comparatively simple physical ideas to a clear understanding of the sophisticated mathematical tools needed for investigating modern polaron physics.Beginning with an introduction to the T-product approach in the theory of a particle interacting with bosonic fields as applied, for example, to the linearized polaron model, the book goes on to deal with the equilibrium state investigation for the Frolich polaron model, the main objective being to derive Bogolubov's inequality for the reduced free energy of the polaron. The third chapter deals with some problems related to the non-equilibrium polaron theory, including polaron kinetics. Finally, alternative methods used in polaron theory are also presented and compared with Bogolubov's method. Copyright (C) Muze Inc. 2005. For personal use only. All rights reserved.