Polymer theory: path integrals and scaling

In this review paper a number of recent topics on polymer theory are discussed. One of the main issues of the present work is to show that scaling theories together with more sophisticated methods gives answers to the raised questions. The here selected topics are connectivity and interactions. The problem of connectivity is especially important in connection with restricted geometries. Here it is shown that simple scaling theories propose a number of results, which can now checked experimentally. Interactions play a dominant role in polymers blends and copolymers and become especially important when disorder effects come into play.