This volume aims to investigate the topic of Substance and Attribute . The way leading to this aim is a dialogue between Islamic and Western Philosophy. Our project is motivated by the observation that the historical roots of Islamic and of Western philosophy are very similar. Thus some of the articles in this volume are dedicated to the history of philosophy in Islamic thinking as well as in Western traditions. But the dialogue between both philosophies is not only an historical issue, it also has systematic relevance for actual philosophical questions. The topic Substance and Attribute particularly has systematic relevance for the actual ontological debate. Christian Kanzian is extraordinary professor of philosophy at the Philosophical Department, Theological Faculty, University of Innsbruck (Austria) and President of the Austrian Ludwig Wittgenstein Society. Muhammad Legenhausen is associate professor of western philosophy at the Imam Khomeini Education and Research Institute in Qom (Iran).