The rapid development of new packings for aqueous size-exclusion chromatography has revolutionized this field. High resolution non-adsorptive columns now make possible the efficient separation of proteins and the rapid and precise determination of the molecular weight distribution of synthetic polymers. This technology is also being applied to the separation of small ions, the characterization of associating systems, and the measurement of branching. At the same time, fundamental studies are elucidating the mechanisms of the various chromatographicprocesses. These developments in principles and applications are assembled for the first time in this book. Fundamental issues are dealt with: the roles of pore structure and macromolecular dimensions, hydrophobic and electrostatic effects, and the determination and control of column efficiency. High-performance packings based on derivatized silica are reviewed in detail. Special techniques are thoroughly described, including SEC/LALLS, inverse exclusion chromatography, and frontal zone chromatography.