This is described as the first critically supervised collected edition. Each volume of music is printed with the cleffings and notes values found in the primary sources. Each has a substantial preface with detailed information about the sources consulted for the works contained in it. Volumes 1-6, however, were not initially designated as pa rt of this edition and were published separately. Although this opera omnia is popularly known as the "Haberl" edition, several editors contributed: Theodor de Witt edited vols. 1-3, Franz Espagne edited vols. 4-8, and Franz Commer edited vol. 9. Haberl himself was responsible for vols. 10-33.