In this chapter, Chenyang Wang argues for the importance of understanding Lacan’s theory of time in the context of both Lacan’s own theoretical structure and the philosophy of time. On the one hand, time is key to understanding Lacan’s theory as a whole. A new temporal perspective can shed light on Lacan’s other concepts and themes including body, language, desire and sexuality. On the other hand, Lacan’s work responds to the contemporary problems about time in the history of philosophy by offering an original account of the subjective existence in time and the meaning of living temporally. After explaining several key interpretative principles that guide the author’s reading of Lacan, the introduction ends with a brief overview of main chapters of this book.