Though best known today for his Old English homilies, the Anglo-Saxon scholar Ælfric also composed, in a "letter" to his fellow monks, a set of Latin liturgical instructions that offer a rare glimpse of what ordinary monks were expected to know and do. This book contains a new edition of the Latin text with a critical apparatus, and the only complete English translation. Commentary and substantial introductory chapters establish the letter's exceptional importance for our understanding of late Anglo-Saxon monasticism and liturgy.