This volume inaugurates the first comprehensive critical edition of the correspondance of Hildegard. Texts of 123 pieces of correspondence make up the volume; the complete edition will comprise 482 letters. The edition brings to fruition the scholarship of the last hundred years concerning the body of lettres and gathers together for the first time the texts from all the important witnesses. Lieven Van Acker throws dramatic new light on the question of authenticity in the introduction to this volume. He has advanced our understanding of the development of the body of Hildegard's correspondence and produced an indispensable tool for researchers.