Types of Medieval Manuscript Books
    Most medieval books contain sacred texts.  Bibles, at least those containing all the books we expect to find in a Bible, were rare because they were so large and usually required multiple bound volumes to contain the text.  The rest are specialized “service books” which guided the official cathedral spiritual ceremonies and household personal practices of Christians from hour to hour, day to day, throughout the months of the “liturgical year.” The liturgical year was measured by liturgies or sacred ceremonies, running from one Easter to the next.  Next in importance and number to sacred texts were those needed by scholarly professions such as doctors, lawyers, and philosophers.  The “humanities” were largely undiscovered, so texts we might identify as “literary” were extremely rare and, consequently, extremely precious when they have survived to the present day.  Finally, some books were custom-made for governments, great families’ households, and occasionally, personal use: account books (Everyman’s “book of account”), estate books, receipt books (i.e., cooking recipes, household maintenance tips, and medicinal formulas), and commonplace books, named for the loci communes or “common rhetorical places,” categories of wisdom and eloquence that should be stored in writing.  These were short passages culled from "auctores" or authorities considered worth remembering.

Types of Religious Books
Bibles (very rare): Most medieval Bibles contained more “books” than are now found in Bibles for the Roman or Protestant Churches, including the “apocryphal” books now thought to have been written after the end of sacred inspiration.  Early Bibles often were large, often in five volumes.  Only in the thirteenth century (1200s) did students at the University of Paris become a reliable customer base for mass-produced (but still hand-made) small, portable Bibles known now as “Paris Bibles,” written in extremely small script on very thin parchment.

Other Religious Books for Priests, Nuns and Monks, Friars, and Lay (non-clergy) Scholars
Books Containing the Order of Christian Mass: From the Latin, “ite misse est” (“it [the service] is over, you are dismissed”), the Mass is the general term for the major ceremonies of reading, singing and other sacred rituals that organized medieval Christians’ spiritual life.  Many specialized "service books" were invented to help priests perform the immensely complex sequences of ritual prayers, songs, and gestures that had to be performed every day of every year.  The "Sanctorale" was a series of changeable ceremonies and texts which celebrated specific church events from Advent (4 weeks before Christmas) to Pentecost (fifty days after Easter).  These each have five parts: Introit, Collects, Epistle, Gradual, Alleluia.   The “Ordinary of the Mass,” which follows and does not change, also has five parts: Kyrie, Gloria, Credo, Sanctus, Angus Dei.  Each part of the Mass requires texts, usually excerpts from the Bible, to be read and/or sung.  The "Temporale" provides the annual rotation of daily celebrations of saints’ days, sung between Masses.  The books below were created to supply those texts.

Missal: From the Latin missale or “mass book,” a very big volume that contains all prayers and biblical texts required to celebrate the Mass throughout the Church Year.  It was a later compilation of several types of books that all were previously needed to piece together each service.

Lectionary: Because Jewish and Christian churches follow a mandate that the entirety of the sacred texts be read to the people over the course of from one to three years, lectionaries guided readers to choose the correct passages appropriate to each part of the year.  Unlike the “missal,” which contains all the prayers needed to celebrate the Mass, including portions of the Bible read therein, the lectionary contains only the sacred text in the calendar order in which it is read.

Sacramentary: Like the missal, the sacramentary contains all the texts needed for the priest who celebrates the Mass, but none of the other texts read or sung by other participants in the service.

Breviary: A condensed compendium of all the year’s sung and read texts for the eight hourly prayers of the Divine Office, often used by mendicant friars like the Franciscans.  In 1228, Francis was given a Roman breviary to which he added the Mass Gospels for his own devotions.  The book remains in a reliquary at Convent of Poor Clares, Assisi.

Laypeople’s Sacred Books--

Gradual: From the Latin “responsorium graduale,” graduals provided the chants the congregation uttered after the epistle and before the agnus dei in the Ordinary of the Mass.  Graduals might have been used by parish priests to teach congregations to play their parts in drama of the Mass.

Psalter: Originally just the Psalms of David, the psalters grew to include a liturgical calendar of the days on which specific psalms would be read (not in biblical order!), as well as the “litany of the saints,” a sequence of prayers (often illuminated) devoted to specific saints revered in the region for which the psalter was made.  The calendar and saints invoked could be used to generally locate the diocese for which the psalter was created, helping us guess its provenance.  Because the Psalms are poems recording private appeals to God, for those who could read and could afford them, Psalters were often popular tools for private meditation and comfort in times of crisis.

Horae: From the Latin, “hours,” the horae were the most commonly owned laypeople’s religious books after the fourteenth century.  They supplied cues for how to respond to abbreviated portions of the Mass when the congregation replied to the clergy celebrating the liturgy, sometimes including musical scores for sung portions.  Horae often began with monthly calendar pages listing saints’ days which, like psalter calendars, could help localize their place of use and usually place of manufacture.  Horae contained many of the Psalms found in psalters, but out of their biblical order and reorganized according to hours of the day and days of the liturgical year, together with passages from various other books of the Bible and prayers for special repeating services. 
The eight “daily offices” or repeated hours of prayer, as laid out in St. Benedict’s monastic rule, were Matins (also “Vigils”) recited at night around 3 AM, Lauds at dawn, Prime at about 6AM (whence “primer,” the morning schoolbook), Terce at 9 AM, Sext at noon, Nones at 3 PM, Vespers at “lamp-lighting time” ca. 6PM, and Compline before going to bed.  References to these hourly prayers are commonplace in legal testimony and in personal letters as a means of locating the author in time from medieval to the Early Modern era—Shakespeare and Jonson lived by these hours, as did Chaucer and Margery Kempe.
The most common repeating services in late medieval liturgies involved prayers associated with Mary, such as the “Little Hours of the Virgin,” the fifteen Gradual Psalms (#119-33), the seven Penitential Psalms (#6, 32, 51, 102, 130, 143), the Litany of the Saints, and the Office of the Dead (a funeral service in two parts, named for their opening words, the Placebo [“I will please the Lord in the land of the living” from Psalm 114, sung in the church] and the Dirige [“Direct my path” from Psalm 5, sung at graveside]).  The Litany of the Saints reads the lives of the martyred saints in the order of their feast days, usually ending with the lives of the (female) virgin martyrs.
For expert scholarship on horae and their use, as well as other private devotional books used by English readers, consult Eamon Duffy, Marking the Hours: English People and Their Prayers 1240-1570 (New Haven: Yale UP, 2006) 242.0942 D858m 2006. 

Secular Books—
Histories, Laws, Religious Commentary:  Histories drawn from Roman authors were popular, as were Latin summaries of Homer’s “Trojan History,” known by authors’ names as “Dares Phrygius” (Dares the Trojan) and “Dictys Cretensis” (Dictys of Crete).  Some nobles commissioned custom-made family histories.  Even after the fall of the Eastern Roman Empire, its colonies tried to preserve Roman law in the form of the “Statutes of Justinian,” a Roman emperor.  As Christianity became more mportant than the increasingly distant memory of Roman law, Church law and doctrine required extensive books containing interpretations of biblical texts and later foundational documents such as St. Augustine’s “City of God” and “On the Trinity.”

Account Books: Account books resemble Excel spreadsheets, and are prepared by scribes to record a person’s or estate’s business transactions.  They can be special purpose for individual projects, like a voyage or construction of a building, or long-term records for the lifetime of a person or institution.  A special subset of account books were schoolmasters’ and governesses’ records of their students’ or charges’ behavior, performance on tests, health, etc.

Estate Books: There is considerable overlap in common usage of the terms “account books” and “estate books,” but the former tend to be extremely repetitive formulas of amounts of money paid, linked to purposes or persons, whereas the latter may include lists of persons employed with salaries, births and deaths of important persons, etc.  Less wealthy people often turned their family Bibles into estate books by recording such information on flyleaves.

Receipt Books: Often misidentified as “recipe books,” the “receipt book” contains the sorts of cooking directions one might expect from the former, but also includes medical formulas for various cures, and formulas for making useful household maintenance substances like polishes, cleaners, etc., together with methods for doing necessary household chores.

Commonplace Books: Commonplace books are the most idiosyncratic of surviving manuscript books because they originate in their makers’ individual interests or occupations.  Ancestors of the modern “diary,” they were constructed over long periods of time by individuals engaged in some intentional practice of self-improvement or preparation for a life’s work.  They usually contain quotations of works by famous authors drawn from print and manuscript books, but they may also contain lists of important ideas or dates or persons, advice for performing repeated tasks, and occasionally private reflections of the sort modern writers record in a “diary” or “day-book.”  For published examples, see:

Byrd, William.  The commonplace book of William Byrd II of Westover, Ed. Kevin Berland, Jan Kirsten Gilliam, and Kenneth A. Lockridge.  Chapel Hill : Omohundro Institute of Early American History and Culture, Williamsburg, Virginia, by the University of North Carolina Press, c2001.  975.5 B99Sb 

Hill, Richard, active 1518-1538.  Songs, Carols, and other miscellaneous poems : from the Balliol ms. 354, Richard Hill's commonplace-book.  Ed. Roman Dyboski, PH. D.  London : Pub. for the Early English Text Society by K. Paul, Trench, Trübner & Co., limited, 1907 (issued in 1908). 820.6 E13 Extra ser. no.101

Jefferson, Thomas.  Commonplace book Jefferson's literary commonplace book.  Ed. Douglas L. Wilson.  Princeton, N.J. : Princeton University Press, c1989.  973.4 J45c 1989.