The Five Books of the Psalter The Midrash on the Psalms, codified in the ninth century A.D., attests to this fivefold division and draws an analogy to the five books of the Torah. While we cannot be certain when this division was introduced, it was very likely an early editorial feature of the book, since the divisions are quite obvious by the concluding doxologies of each book: Book 1—Psalms 1–41 Concluding doxology: 41:13 Book 2—Psalms 42–72 Concluding doxology: 72:18–19 Book 3—Psalms 73–89