This book provides an account of the recent advances in our understanding of the role of proteases under physiological and pathological conditions. It reviews the contributions that have been made in the fields of biochemistry, molecular biology, medicine, agriculture and ecology. In addition there is an account of the growing number of practical applications in biotechnology, reflecting the fact that peptidases are major targets for medical and agricultural purposes. The book shows how the numerous protease structures are essential for drug design. The contributions place special emphasis on cysteine, aspartic and metalloproteases and their role in physiological and certain pathological states. Another focus is the classification and nomenclature of peptidases and a review of those proteases currently under the most intensive investigation. The book provides an informative introduction for teachers and newcomers to the field, such as graduate students, while providing a valuable source of material and ideas for the academic and industrial researcher in areas including biochemistry, medicine, agriculture and biotechnology.