In The Middle Ages, religious books were reserved for only the most wealthy. It was they (after all), who were educated enough to use them. The literacy rate in The Middle Ages was very low (with less that 3 percent of the Population of Europe being age to read). Prior to The Printing Press and the mass production of books, many volumes of work were hand copied and hand illustrated (or illuminated), by Religious (Friars, Priests and Monks). It would take many months (perhaps years to create the larger works). Conversely, The Bible was only available to Priests (and the wealthy). The average person did not own one. The Psalter was one of the first form of religious books used in standard religious ceremonials. Psalters were books that contained The Biblical Psalms, The Litany of The Saints and a Liturgical Calendar. These works served until the mass production of “The Book of Hours” came forth (regulating The Psalter to mostly religious use). Other later versions would include a Lectionary and Hymnal.