Over the last century, the centrality of proteins to life on earth has become increasingly clear - from forming crucial molecules such as antibodies in the immune system to acting as catalysts for specific reactions, and as signalling molecules between cells. In fact, the more they are studied, the more proteins continue to reveal new and exciting functions. Indeed, by studying amino acid sequences it is even possible to unravel some of the mysteries of evolution itself. Introduction to Protein Science, 3rd edition, provides a rich and broad introduction to this fascinating field by covering not only the structure and function of proteins, but also the methods and experimental techniques used to study them. The practical applications of our knowledge to diverse fields such as biotechnology and medicine are emphasized throughout, to help students appreciate the relevance of the subject to the real world.