Psalms – Book 2
It is not known when the Psalms were separated into five books, but the separation dates back to before the oldest extant manuscripts, which are compiled in the Masoretic Text. The Psalms of the second book share some general differences with the Psalms of the first book.
The Hebrew word in reference to God is emphasised differently in the first two books of the Psalms. According to Franz Delitsch, in Book One the name Jehovah occurs 272 times and Elohim only 15. However, in Book Two, Elohim occurs 164 times and Jehovah only 30 times.
In the first book of Psalms, 37 of the 41 are specifically attributed to David, and the four remaining are unattributed. David is the only known Psalmist in Book One.
In the second book of Psalms, David authored 18 of the 31, more than half. But in this second book, other Psalmists appear: Asaph and Solomon have one each, seven perhaps eight Psalms belong to the Sons of Korah, and three have no author listed.