Do patents facilitate or frustrate innovation? Lawyers, economists, and politicians who have staked out strong positions in this debate often attempt to validate their claims by invoking the historical record—but they frequently get the history wrong. gets it right. Bringing together thoroughly researched essays from prominent historians and social scientists, this volume traces the long and contentious history of patents and examines how they have worked in practice. Editors Stephen H. Haber and Naomi R. Lamoreaux show that patent systems are the result of contending interests at different points in production chains battling over economic surplus. The larger the potential surplus, the more extreme are the efforts of contending parties-now and in the past-to search out, generate, and exploit any and all sources of friction. Patent systems, as human creations, are therefore necessarily ridden with imperfections. This volume explores these shortcomings and explains why, despite all the debate, historically US-style patent systems still dominate all other methods of encouraging inventive activity.