Definition, characterization, nature and mode of action, composition, occurrence, manufacture, recent nomenclature, and classification of enzymes and their significance in food preparation are discussed. Marketed food enzymes, their sources, applications, units, and assay methods are reviewed. Sources of information and their usefulness are critically reviewed. The review concludes that food enzymology, by its importance and advanced stage, should stand on its own, attended by an appropriate society independent from the other branches of enzymology or food technology.