This book gives a state-of-art overview on aspects of micro- and nano-mechanics of polymers, polymeric blends, and composites. Major issues include: experimental techniques to study the mechanical performance of polymer systems especially in respect with molecular, supermolecular and filler architectures on suitable model materials; prediction methods of the mechanical performance (short- and long-term properties); modeling tools and approaches. All these aspects are highlighted on polymeric systems of both academic and practical relevance.