For over eight hundred years, philosophers―men and women―who called themselves Cynics, literally "dogs" in their language, roamed the streets and byways of the Hellenistic world, teaching strange ideas and practicing a bizarre way of life. Among them, the most important and distinctive was Diogenes of Sinope, who became the archetype of Classical Cynicism. In this comprehensive, thoroughly researched, and engaging book, philosopher Luis E. Navia undertakes the task of reconstructing Diogenes' life and extracting from him lessons that are valuable in our time. The book is divided into five chapters. Chapter 1 provides a biographical sketch of Diogenes constructed on the basis of ancient testimonies. In Chapter 2, the practice of Cynicism, as exemplified by Diogenes, is elucidated. This "war against the world," as Navia describes it, especially the rhetoric of Cynicism, was the primary medium used by the Cynics to convey their message. Chapter 3 clarifies the roots and basis of the Cynic metamorphosis, that is, the process by which Diogenes transformed himself into a dog. This process involves complex psychological, sociological, and philosophical factors, chief among which was Socrates' influence on Diogenes through the agency of Antisthenes. Chapter 4 reconstructs the philosophy of Diogenes by identifying twelve principles of his thought. In Chapter 5, the influence of Diogenes is discussed. Navia emphasizes the vast difference between Diogenes' ideas and style of life on the one hand and, on the other, what is nowadays called cynicism. The book provides abundant references to ancient testimonies and modern scholarship. It includes an extensively annotated translation of Diogenes Laertius's biography of Diogenes and a comprehensive bibliography.