Forty years after the term affinity chromatography was introduced, this mode of chromatography remains a key tool in the armory of separation techniques that are available to separation and interaction scientists. Affinity chromat- raphy is favored because of its high selectivity, speed, and ease of use. The rapid and selective isolation of molecules using affinity chromatography has allowed a better understanding of biological processes, accelerated the identi- cation of target molecules, and spawned new process areas such as immobilized enzyme reactors. It has had ubiquitous application in...