Book excerpt: This book is an interpretation of one of the central themes of Mulla Sadra’s philosophy of existence known as ‘transubstantial change’. It provides, for the first time in English, a comprehensive analysis of transubstantial change in light of Sadrian ontology and its impact on some philosophical issues such as identity, values, and truth. As the author elucidates, in transubstantial change nothing is indestructible and everything in the world, including substance, is inconstant renewal.