The human-nonhuman primate (NHP) interface is broad, complex and abounds with the opportunity for infectious disease transmission. While current research focuses largely on disease ecology in great apes, the role of diseases in monkeys at the human-NHP interface and One Health is often neglected. Monkeys may lack the physical size and charisma of great apes, but the human-NHP interface is mostly driven by contact with monkeys rather than great apes. Millions of monkeys share the environment with humans in free-ranging contexts and within laboratory and captive settings. Within each of these contexts the role that monkeys play as a reservoir for human infections is poorly understood as is the impact that this contact has on the health of monkeys. This edited volume contains a four chapter long introduction on the general theme, disease-host co-evolution and diseases in the context of sociality and behavior prepare the reader with the background knowledge for the subsequent sections on the “Role of Neglected Monkey Diseases in One Health” and “Neglected Diseases in Monkeys in the Context of the Monkey-Human Interface”. The book ends with a synopsis that summarizes the book's content and provides a current example of how researchers working on monkey diseases are thinking outside the box.