Answering a long-standing need in the pharmaceutical and biotechnology fields, this definitive reference focuses on the biology, pharmacology, and therapeutic applications of endogenous peptide mediators and their analogues. It takes peptide science beyond chemical synthesis strategies and into the realms of peptide biology and therapeutics. It presents the overall contribution peptide science has made to molecular, cellular, and whole organism biology, while discussing future targets and therapeutic applications. With the mounting worldwide interest in the therapeutic potential of peptides, this is an indispensable work for researchers.