Interest in Gregorian chant has always been alive among musicologists and those devoted to preserving early church music in all its haunting simplicity. Willi Apel's extensive survey of the chant describes the evolutionary processes of its long history as well as its definition and terminology, the structure of the liturgy, the texts, the notation, the rhythm, the tonality, and the methods and forms of psalmody. Under the heading "Stylistic Analysis" it offers chapters on liturgical recitative, the free compositions according to types, Ambrosian chant (by Roy Jesson), and Old-Roman chant (by Robert J. Snow). A short conclusion, titled "Prolegomena to a History of Gregorian Style," completes this impressive volume. Book jacket.