"In this historically wide-ranging study, Dustin Klinger looks at an issue that was pivotal in both ancient Greek and medieval Arabic philosophy. Taking the story from Aristotle to Avicenna and his reception, the book is an important contribution to the exciting field of logic and philosophy language in the Islamic world."--Peter Adamson, Professor of Philosophy at LMU Munich "Klinger's study of medieval Arabic and Islamic views of the copula--the crucial element that links subject and predicate in a proposition--is remarkable on a number of counts: its historical range, the number of sources it incorporates, and its engagement with modern philosophical discussions of the analysis of propositions. It is an important contribution to the field of Arabic-Islamic philosophy and logic."--Khaled El-Rouayheb, Jewett Professor of Arabic at Harvard University "This book is an extraordinary tour through the long, fascinating, and neglected history of Arabic logic, focusing on a fundamental doctrine central to the analysis of propositions and inferences. The Arabic texts quoted in translation provide rich insight into concerns and methods of schools of logic with which we should be more familiar. The book is indispensable for anyone interested in Islamic intellectual history and particularly for those working on post-Avicennan philosophy or theology."--Tony Street, Assistant Director of Research in Islamic Studies at University of Cambridge