AbstractThis review considers the structure of cellulose and hemicellulose, enzymology of cellulases and xylanases (sources, enzyme assays, substrate specificity, kinetics and subsite mapping, inhibition, transferase activity, mode of action, synergism, catalytic mechanism), other characteristics of cellulases and xylanases (induction and regulation, physicochemical properties, their multiplicity, adsorption, architecture and classification, structure/function relationships) and applications.