The only manuscript preserving this collection of letters, in the British Library, is damaged at the beginning, thus depriving us of the author's name. However, the letters of the Anonymous Professor, a scholar and headmaster of a private school in Constantinople in the mid tenth century, comprise an important source for our knowledge of education and intellectual life in Byzantium in this period. The present edition, which aims to fulfil the need expressed by many scholars for a new, fully annotated critical edition of the letters, attempts to reconstruct the main events in the life of the Professor, along with his educational and, more generally, intellectual pursuits. Full summaries of the letters are provided. Information about the Professor's correspondents, many of whom belong to the milieu of the imperial court and the church, is presented and examined. The critical edition of the letters together with accompanying notes comprises the core of the book while detailed indices are supplied at the end.