Final answer:
The final book of the Psalter reflects on themes such as the life of King David, music and composition, and Christian interpretations of the Psalms. It features lavish illustrations of King David and introduces changes in the text, including different colors of ink and a switch in the version of the Psalms.
Step-by-step explanation:
The final book of the Psalter reflects on various themes, including the life of King David, the role of music and composition, and the Christian interpretations of the Psalms as a prefiguration of Christ's life, death, and resurrection. In this final book, there are lavish illustrations that depict King David as a musician and composer, sitting atop a boulder and playing his harp in an idyllic pastoral setting. The book also introduces changes in the text itself, with different colors of ink and a switch from the Roman version of the Psalms to the Gallican version.