To say that the sentence "snow is white" is true, is to say that snow is white, and nothing more. Because of this apparent redundancy of the truth predicate for sentences, deflationists maintain that truth is a notion lacking in content and therefore not a worthy subject for philosophical analysis. This book builds on the work of Jeffrey Ketland in demonstrating that semantic definitions of truth for formalised languages, in particular those of Alfred Tarski and Saul Kripke, are richer than their deflationary rivals, in the sense that they enable us to derive results that cannot be derived via deflationary theories. This deductive power of semantic theories of truth suggests that truth is, contrary to the deflationists' view, a substantive notion that warrants continued philosophical analysis.The author is a Senior Lecturer in Mathematics at the University of Bolton. His academic interests include abstract algebra, in particular group theory, ring theory and Galois theory, the philosophy of science, and the philosophy of logic. He lives in south Manchester.