This book offers an overview of Putnam's ideas, his key writings and his contributions to the various fields of philosophy. Thematically organized, the book begins with Putnam's work in the philosophy of language and shows how his theory of semantic externalism serves as a lynchpin for understanding his thought as a whole. Crucially, the author also examines the ways in which Putnam has shifted his position on some key philosophical issues and argues that there is in fact more unity to Putnam's thought than is widely believed. An entire chapter is devoted to Putnam's pragmatism and the possibilities this provides for revitalizing contemporary philosophy. This is the ideal companion to study of this hugely influential thinker.