Professor Maz'ya - one of the main developers of the modern theory of Sobolev spaces - contributed to the theory in many various directions. The strong influence of his fundamental works is traced in recent results presented in this volume from world-recognized specialists. The topics cover various aspects of the theory of function spaces, including Orlicz-Sobolev spaces, weighted Sobolev spaces, Dirichlet spaces, Besov Spaces with negative exponents, fractional Sobolev spaces on half-spaces and sharp constants in the Hardy inequality, Maz'ya's capacitary analogue of the co-area inequality adapted to the setting of metric probability spaces, Hardy-Sobolev-Maz'ya inequalities, converse of Maz'ya's inequality for capacities, Hersch's isoperimetric inequality, isoperimetric Hardy type and Poincare inequalities on metric spaces, isoperimetric problems in connection with Carnot groups, pseudo-Poincare inequalities and applications to Sobolev inequalities, Sobolev inequalities on fluctuating domains, Sobolev homeomorphisms and composition operators, extension domains for functions with bounded variation.