While books have been written on many topics of Polymer Science, no compre hensive treatise on long chain branching has ever been composed. This series of reviews in Volume 142 and 143 of Advances in Polymer Science tries to fill this gap by highlighting active areas of research on branched polymers. Long chain branching is a phenomenon observed in synthetic polymers and in some natural polysaccharides. It has long been recognized as a major mole cular parameter of macromolecules. Its presence was first surmised by H. Stau dinger and G. V. Schuh (Ber. 68, 2320, 1935). Interestingly, their...