The purpose of this volume is above all to serve as a key to the deciphering of melodies written in the Middle Byzantine notation. In addition, it offers an introduction to Byzantine chant in a wider sense, dealing with topics such as chant transmission before the neumes, the varieties of Byzantine musical notations, words and music in Byzantine chant, Byzantine and Western neumatic notations, modes, melody and intervals, and the development of the musical genres. Coming into use around AD 1150, the Middle Byzantine musical notation is the earliest notational type of Byzantium that can be transcribed with reasonable accuracy. Consequently, the musical content of manuscripts earlier than c. 1150 can only be fully understood through Middle Byzantine versions. The Middle Byzantine notation continued to be used in Greek Orthodox Churches until the beginning of the 19th century. Christian Troelsgård presents a panorama of the styles of Byzantine chant, ranging from simple psalmody to highly elaborate and melismatic pieces. To illustrate the various musical genres and give the reader a first-hand impression of the original sources, a set of specimens of musical manuscripts with known date and provenance is included. The text presents more than sixty musical examples with transcription into staff notation and is provided with an annotated bibliography. The volume is conceived as an update of H.J.W. Tillyards Handbook of the Middle Byzantine Musical Notation (Copenhagen 1935), one of the first publications to appear in the series Monumenta Musicae Byzantinae.