The Cynic movement occupies a unique and often provocative place in the history of ancient philosophy, defined by its radical critique of social conventions, rejection of materialism, and commitment to an austere way of life in accordance with nature. Emerging in the late 5th century BCE, and flourishing through the Hellenistic and Roman periods, Cynicism has been both revered and reviled for its uncompromising approach to personal freedom and ethical integrity. Though frequently overshadowed by the more systematized philosophies of Platonism, Aristotelianism, and Stoicism, the Cynic movement exerted a lasting influence on Western thought, shaping the discourse on virtue, happiness, and the role of the individual in society. This book aims to provide a deep historical and conceptual introduction to the movement, analyzing its origins, central tenets, key figures, and the literary sources that allow us to reconstruct its ideas.