This, the first Wiley publication of a Polymer Network Group Review, presents articles resulting from the 13th Polymer Network Group conference that took place in the Netherlands in September 1996. The scope of the conference was "Chemical versus Physical Networks: Formation and Control of Properties". The resulting contributions provided new insight into recent trends in liquid crystalline and anisotropic networks, nanostructures and new developments in network theory and modeling. The papers published in this volume have been divided into 7 sections: Thermoreversible and Biopolymer Gels Formation of Covalent Networks Liquid Crystalline Networks Characterisation of Networks Critical Gels Heterogeneous Gels Swelling of Networks