In the early ages of the Church the Office of the Holy Communion was contained in several separate volumes, one for the Epistles, one for the Gospels, another for the anthems and a fourth for the service itself with the Collects. These four volumes were eventually united into one volume under the name Missal, i.e., pertaining to the Mass, and therefore, it is the old title of the book containing all that pertains to the Office of the Holy Communion.