This book arises from a research and publication project funded and organised by the Groningen Centre for Law and Governance (GCL): the project ‘Content and Effect of Contracts: the CESL in the European Multi-Level System of Governance’. I have had the honour and pleasure to coordinate and carry out this project in 2013– 2014 in cooperation with other 22 European scholars, affi liated to 15 universities based in 5 countries (England, Germany, Italy, the Netherlands and Turkey): the Universities of Amsterdam (UvA), Bremen, Exeter, Groningen, Istanbul (Türkisch- Deutsche Universit?t), Kassel, Leiden, Lüneburg, Oldenburg, Osnabrück, Rome (La Sapienza), Tilburg, Utrecht, Warwick and Würzburg. The contributions included in this volume represent the fi nal product of a research process whose fi rst results were presented at the international workshop ‘Content and Effect of Contracts: the CESL in the European Multi-Level System of Governance’, which took place in Groningen on 31 May–1 June 2013. This book is structured into two parts. The fi rst part contains fi ve essays exploring the origin, the ambitions and possible future role of the Common European Sales Law (CESL) in general and its Chapter 7, in particular, for European contract law and contract practice. The second part contains specifi c comments to each of the provisions laid down in Chapter 7 CESL (Art. 66–78).