This proposal continues the study of the static and dynamical properties of polymeric systems into regimes of higher concentration. The major effort in the future will be directed towards developing systematic methods for treating the physics of more concentrated systems, in accord with our plan to climb up the ladder of concentration step by step. As the concentration rises, he encounter richer and richer physics. He focus especially on: (A) dynamics of many chain systems; (B) fundamental study of rubbers and gels; (C) semimacroscopic dynamics at first order phase transitions. His goal is to construct a conceptually sound semiquantitative theory of polymer and related systems capable of direct confrontation with experiment.