Let’s start off with some basic terminology. This blog will study psalters. A psalter is a book of Psalms outside of the bible. It could be freestanding, as many medieval psalters were. Over on the right you will see links to a few examples of medieval psalters. This Wikipedia page has a listing of other psalters. Psalters can have additional prayers and other material added. They are the precursors to the late medieval Book of Hours. Some modern liturgical books like the Book of Common Prayer and books derived from it have complete psalters.
Breviate psalters are an abbreviated version of the book of psalms. The earliest examples survive from the 9th century and are credited to the Venerable Bede. They continued to be popular up into the period of the Books of Hours. Breviate psalters are the topic of my distilled prayer project.