Enzyme Functionality serves as a conduit for trailblazing research in enzyme engineering-relating current understanding of sequence families, the new notion of enzyme structure classes, and modern methods in protein engineering, design, and directed evolution to accelerate the development of novel enzyme functionalities. This reference gathers the diverse perspectives of nearly 80 scientists from around the globe and surveys all leading rational and random approaches to the artificial evolution of enzymes. Citing more than 1500 notable works, it outlines assays for enzyme activity, stability, and specificity and a wide variety of site-directed, redesign, and evolutionary engineering methods.