The past 25 years has seen the emergence of a wealth of data suggesting that novel biological functions of known proteins play important roles in biology and medicine. This ability of proteins to exhibit more than one unique biological activity is known as protein moonlighting. Moonlighting proteins can exhibit novel biological functions, thus extending the function of the proteome, and are also implicated in the pathology of a growing number of idiopathic and infectious diseases. This book, written by a cell biologist, protein evolutionary biologist and protein bioinformatician, brings together the latest information on the structure, evolution and biological function of the growing numbers of moonlighting proteins that have been identified, and their roles in human health and disease. This information is revealing the enormous importance protein moonlighting plays in the maintenance of human health and in the induction of disease pathology. Protein Moonlighting in Biology and Medicine will be of interest to a general readership in the biological and biomedical research community.