Grateful thanks to The Leverhulme Trust for its enabling support of this project. Thanks to Alessandra Tosi, Catherine Heygate, and Bianca Gualandi of Open Book Publishers for their help and encouragement. The music was researched and recorded by the staff and students of the Conservatoire national supérieur de musique et de danse de Paris (Director: Bruno Mantovani), and we should particularly like to thank students from the Department for Training Sound Engineers (Head of Department: Denis Vautrin); the class specialising in recording, artistic direction of recording and post-production techniques (Professor: François Eckert): Guillaume Defer, Raphaël Faverjon, Mathilde Genas, Gaëtan Juge; students from the Department of Musicology and Musical Analysis (Head of Department: Corinne Schneider), in particular the class for the professions associated with musical culture (Professor: Lucie Kayas); students from the Department of Vocal Training (Head of Department: Jean-Marc Demeuré); and students from the Department of Early Music (Head of Department: Pascal Duc). Jean Baptiste Fournier prepared the Notes on the composers and the musical works mentioned. Claude Maury selected the musical extracts and prepared the students. Martin Gester, musical director of the Parlement de Musique (Strasbourg), conducted pieces 13 and 14. Kate Tunstall and Caroline Warman would like to thank Sarah Gracie for her critical and creative reading of the translation. Marian Hobson gratefully acknowledges the advice of John Easterling, Trinity College, Cambridge; Mark Darlow, University of Cambridge; Michel Noiray, CRNS; Graham Sadler, University of Hull; Catherine Walser and François Jacob (Director), Institut et musée Voltaire, Bibliothèque de Genève, Geneva. She would like to thank William St. Clair for having suggested the Open Access format, and for making the online publication possible in the first instance; Nicole Vérat-Pant for her long-term support and advice; and most especially, the interest and skill of Max Engammare, CEO of Droz, the publisher of the paper edition in French. Radu Suciu, Research Associate for Digital Humanities, University of Geneva, has been a constant source of advice and suggestions.