The book provides a broad and topical perspective of the sources of modern contract law. It examines the creation of contract law as a multi-pronged occurrence that involves diverse types of normative content and various actors. The book encompasses both a classical perspective on contract law as a state-created edifice and also delves into the setting of contractual rules by non-state actors. In so doing, the volume thoroughly analyses present-day developments to make sense of shifting attitudes towards the overall regulatory paradigm of contract law and those that reshape the classic view of the sources of contract law. The latter concerns, in particular, the digitalisation of markets and growing trends towards granularisation and personalisation of rules. The book builds on the EU private law perspective as its primary point of reference. At the same time, its reach goes far beyond this domain to include in-depth analysis from the vantage points of general contract theory and comparative analysis. In so doing, it pays particular attention to theoretical foundations of sources of contract law and values that underpin them. By adopting such diversified perspectives, the book attempts to provide for a better understanding of the nature and functions of present-day contract law by capturing the multitude of social and economic dynamics that shape its normative landscape. The volume gathers a unique and distinguished group of contributors from the EU, USA and Israel. They bring research experience from various areas of private law and contribute with diverse conceptual perspectives. Stefan Grundmann is Professor of Transnational Law and Theory at the European University Institute, Florence, Italy, and Professor of Private and Business Law at Humboldt-University, Berlin, Germany. Mateusz Grochowski is a Senior Research Fellow at the Max Planck Institute for Comparative and International Private Law, Hamburg, Germany, Assistant Professor at the Institute of Law Studies of the Polish Academy of Sciences, Warsaw, and Fellow at the Information Society Project, Yale Law School, United States.