Enzymes are the spirit of the living cells. No metabolic reaction will occur in the cell without enzymes. A Biologist can not think for life without enzymes, we can not think of studying any branch of biochemistry and biotechnology without enzymes. These are the enzymes which play magic in the field of biotechnology. The present book provide basic text in a concise form that permits updating across the whole field of enzymes. The present book is having the quality of having condensed material but with full information. The book covers almost all the aspects for students of the enzymes. The book will be much useful for masters level student as well as young research scholars. The book de4als with nomenclature and classification of the enzymes, techniques for enzyme isolation, techniques for enzyme assay's, intracelluar localization of the enzymes, technology used in the purification of the enzymes, determination of molecular weight of the enzyme proteins, isoenzyme, multienzyme complexes and multifunctinal enzymes, feedback control of the enzymes, kinetics of enzyme reactions, enzymes, inhibitors, allosterism, mnemonical enzymes, mechanism of enzyme reactions, immobilization of enzymes and biotechnological perspectives. The book has been written in simple language, easily understandable by the students. Chapters have been written keeping in mind the syllabi of enzymes and enzyme technology in various universities at the masters level. The book should be of invaluable help to the students, researchers and all those interested in the detailed knowledge of the enzymes.