41:13 Doxology Concluding Book 1. Each of the five books of the Psalter ends with a doxology (see also 72:18-19; 89:52; 106:48; 150:6); three do not seem to be part of their psalms (41:13; 72:18-19; 89:52). Psalm 150 as a whole concludes both Book 5 and the Psalter.