Last year we were all deeply saddened by the death of Psalms scholar Gerald Wilson. Wilson unlocked many doors for psalms study and had a major impact on my own study of the book. In fact, having read Wilson I dedicated a major paper to the psalter, which eventually was published as my first book, Singing In The Reign: The Psalms and the Liturgy of God's Kingdom. Below is a short summary of an overview of the structure of the psalms, largely inspired by his work.
Gerald Wilson, a student of Brevard Childs, has made a major contribution to Psalms studies by looking at the canonical shape of the Psalter itself. He discerns a theological shape behind the five book structure of the Psalter. The five books are arranged differently. Books I-III are organized around Davidic royal psalms, which function as “seams.” Books IV-V seem to be organized differently, revolving around psalms of hllwyh-hwdw. Wilson shows how the first three books are concluded with Davidic psalms. Each of these psalms concludes with a benediction including a double amen.
Furthermore, these psalms seem to involve a subtle movement. Wilson traces the rise and fall the of the Davidic kingdom in these seam psalms. Indeed, the first book is entirely composed of Davidic psalms. Despite having no explicit royal themes, Psalm 41 is clearly a Davidic psalm functioning as the conclusion of Book I, containing the double amen doxology. Book II ends with Psalm 72, which has the superscription, “A psalm of Solomon.” The psalm’s interesting post-script, “The prayers of David, the son of Jesse, are ended,” leads one to conclude that the psalm is meant to be read as a song sung by David “for” Solomon. The psalm is a celebration of the worldwide dominion of the Davidic kingdom and also ends with a benediction concluding with a double “Amen,” as Psalm 41 did. Finally, Psalm 89, concludes Book III. Though the psalmist is not David, the theme of the psalm is clearly the Davidic dynasty. Following the pattern of Psalm 41 and Psalm 72, Psalm 89 ends a double amen benediction.
As David was central in Book I, the shape of Books II-III likewise point to a focus on the Davidic king. Though the books contain psalms ascribed to the priestly sons of Korah and Asaph, a second Davidic collection (51-72) is placed at the center of the arrangement. This organization revolves around David:
Thus Books II-III exhibit a clear shaping around the person of David.
Within the shape of the Psalter there is a subtle movement from lament to praise. Furthermore, we might detect a sketch of Israel’s history in the arrangement of the seam psalms. Book I seems to conclude with David’s death. Books II-III seem to recount the rise of the kingdom under Solomon (Psalm 72) and the eventual defeat of the Davidic king, leading to the exile. Psalm 89 seems to describe the failure of God’s promises to David.
Wilson goes on to describe the Mosaic imagery and the regal images of God found in Book IV as a response to the crisis is exile: God is king and always has been—even long before the Monarchy was established. In addition, the Exodus themes of Book IV can be interpreted as reflecting the hope for a New Exodus, in which God will once again deliver his people from foreign oppression. Thus, after the the exile is described in Psalm 89, the psalter then turns to the hope of restoration. In fact, Book IV concludes with a summary of salvation history, from creation up to the restoration (Ps 104-106). Finally, the dominance of praise and rejoicing in Book V may be understood in relation to the fulfillment of restoration hopes. Indeed, the first psalm of book five seems to underscore restoration themes.
 Gerald Wilson, “The Use of Royal Psalms At The ‘Seams’ of the Hebrew Psalter,” JSOT 35 (1986): 87-88.
 Gerald Wilson, “Evidence of Editorial Divisions In The Hebrew Psalter,” Vetus Testamentum 3 (1984), 349-352.
 All of the superscriptions in Book I attribute the Psalms to David. In the LXX every single Psalm has a Davidic superscription. However, in the MT Psalms 10 and 33 have no heading at all. It should be noted that in the LXX, Psalm 10 (in the MT), is part of the previous Psalm, while the LXX version of MT 33 is ascribed to David. Wilson argues that a Psalm with no superscription is meant to indicate its link with the Psalm prior to it. Wilson, “Editorial Divisions,” 338: “In the first three books of the Psalter there are only four psalms which are completely ‘untitled’ (x, xxxiiii, xliii and lxxi). For each of these there is strong manuscript tradition for combination with the immediately preceding psalm. . .”
 See Wilson, "Royal Psalms," 87.
 Robert Cole, The Shape and Message of Book III (Psalms 73-89) (Sheffield: Sheffield Academic Press, 2000), 182: “Psalm 72 is the culmination of David’s prayers, according to the final verse (20) of its doxology. . . thereby interpreting the superscription as ‘for’, not ‘by’ Solomon.”
 Psalm 72:18-19: “Blessed be the Lord, the God of Israel, who alone does wondrous things. Blessed be his glorious name for ever; may his glory fill the whole earth! Amen and Amen!”
 In the MT the psalmist is not identified in Psalms 66-67, and Psalm 86 is attributed to David. In the LXX only Psalm 66 (LXX 65) and Psalm 86 (LXX 85) are attributed to David. In this it may also seem that the final Korah collection is structured around a Davidic Psalm:
84-87 = Korah
85 = David
86-88 = Korah
 Many scholars only recognize 42-83 as a single unit, describing it as the Elohistic Psalter, since these Psalms refer to God as “Elohim.” However, this chiastic structure shows that the collection extends through the second Korah collection. David C. Mitchell, The Message of the Psalter (Sheffield: Sheffield Press, 1997), 71.
 Psalms 38-41 seem to describe David nearing the end of his life, e.g.: “There is no soundness in my flesh because of thy indignation; there is no health in my bones because of my sin. . . My heart throbs, my strength fails me; and the light of my eyes – it also has gone from me” (38:6, 10); “Behold, thou has made my days a few handbreadths, and what is the measure of my days; and my lifetime is as nothing in thy sight/ Surely every man stands as a mere breath. . . For I am thy passing guest, a sojourner like all my father” (39:5, 12); “My enemies say of me in malice: ‘When will he die, and his name perish?’. . . They say, ‘A deadly thing has fastened upon him; he will not rise again from where he lies’” (41:5, 8).  Wilson, "Royal Psalms," 215.
 Mitchell, The Message of the Psalter, 243: “I would suggest that Psalm 89 can be read as representing the stricken king and Book IV (90-106) as representing the ensuing exile.”
 Mitchell, The Message of the Psalter, 184-185.