The two companion volumes of Advances in Polymer Science numbers 142 and 143 deal with modern aspects of long-chain branching in synthetic polymers. The long-chain architecture is now increasingly used as a design tool for targetted polymer properties. The synthetic aspects cover branching by cationic polymerization, asymmetric branching, poly(macromonomers), dendrimer-polymer hybrids and hyperbranched polymers. Three contributions cover theory and simulation of branching, solution properties, and melt flow of branched polymers, respectively.