The fundamental distinction between the two concepts of Hermetism and Hermeticism, despite their synonymous usage in a significant portion of the scholarly literature, represents two distinct stages in the evolution of the Hermetic tradition. Hermetism refers to the corpus of philosophical-religious texts and doctrines of the first to fourth centuries CE in Alexandria, which incorporated a synthesis of Egyptian, Greek, Jewish, and Gnostic elements. By contrast, Hermeticism denotes the living and multifaceted tradition that began in the Middle Ages with the translation of texts into Arabic and Latin and, through a complex process of transmission, transformation, and reinterpretation, became an influential current in alchemy, natural magic, Renaissance philosophy, and ultimately psychology and emergent spiritualities. Adopting a genealogical and historical-critical approach, the present essay offers a stage-by-stage analytical timeline, demonstrating that this current is not a linear process but rather a complex network of continuities and ruptures, translations and distortions, revivals and rereadings. Through analysis of primary sources—including the Hermetic corpus, the Asclepius, and alchemical texts—and drawing on recent findings in papyrology and critical editions, the study provides a comprehensive map of the two-thousand-year evolution of this tradition. The milestones of this trajectory include the period of transmission to the Islamic world (8th–12th centuries), the Renaissance revival under Ficino (15th century), the Casaubon crisis and historical critique (17th century), and the modern esoteric revivals (19th–21st centuries). This distinction transcends a merely terminological issue, offering a framework for analyzing and understanding the dynamic process of transmission and transformation of spiritual traditions across different historical-cultural contexts. The findings carry important implications for the fields of intellectual history, philosophy of religion, Western esotericism, and comparative religion, and demonstrate how ancient texts are not merely preserved but recreated and reproduced in the process of cultural transmission.