The Qumran scrolls (found near the Dead Sea) show that the Psalms were divided into five volumes:
- Book 1 - Trust in times of testing (chapters 1-41).
- Book 2 - Confidence in God stressed (chapters 42-72).
- Book 3 - Resting in His mercy (chapters 73-89).
- Book 4 - Assurance and praise (chapters 90-106).
- Book 5 - Variety of themes (chapters 107-150).