This is the first book-length study in English of the interpretative and philosophical approach of the commentaries of Simplicius of Cilicia (c. AD 530). Simplicius work marked by doctrinal complexity and scholarship is unusually self-conscious learned and rich in its sources and he is therefore one of those rare authors who is of interest to ancient philosophers historians and classicists alike. Here Han Baltussen argues that our understanding of Simplicius methodology will be greatly enhanced if we study how his scholarly approach impacts on his philosophical exegesis. His commentaries are placed in their intellectual context and several case studies shed light on his critical treatment of earlier philosophers and his often polemical use of previous commentaries. Philosophy and Exegesis in Simplicius not only clarifies the objectives pre-suppositions and impact of Simplicius work but also illustrates how as a competent philosopher explicating Aristotelian and Platonic ideas he continues and develops a method that pursues philosophy by way of exegetical engagement with earlier thinkers and commentators. The investigation opens up connections with broader issues such as the reception of Presocratic philosophy within the commentary tradition the nature and purpose of his commentaries and the demise of pagan philosophy.