Who wrote it — and it's not just David
Psalms is the Bible's only book with a genuinely mixed byline. David is credited with roughly half the collection (73 psalms carry his name in their superscription), but the rest come from a wide circle of other contributors: Asaph and his guild of temple musicians (Psalms 50, 73–83), the sons of Korah (42–49, 84–85, 87–88), Solomon (72, 127), Moses (90 — the oldest psalm in the book, predating David by centuries), Ethan the Ezrahite (89), and a large number left anonymous. The collection wasn't written in one sitting or even one century; it was gathered and arranged over roughly a thousand years, from Moses' era through the return from Babylonian exile.
That compiled-not-composed origin matters for how you read it. Psalms isn't a single argument building toward one conclusion the way Romans or Mark is. It's closer to a hymnal — a working songbook shaped by the worship life of Israel across generations, with each contributor writing out of a real, specific circumstance (a battle, a betrayal, a coronation, an exile) that the poem itself rarely spells out in full.
The structure: five books, one repeating signature
Jewish tradition, going back at least to the rabbis of the Mishnah, divides the Psalter into five "books" that consciously echo the five books of the Torah — as if Israel's own hymnal was patterned after the Law it was written to accompany. Each book closes with a doxology (a short burst of praise) that functions like a chapter break, and the book's very last psalm, 150, is itself one long doxology serving as the finale for the entire collection.
Almost entirely Davidic. Opens with Psalm 1's "two paths" (the righteous vs. the wicked), setting the interpretive lens for everything that follows. Closes: "Blessed be the LORD, the God of Israel, from everlasting to everlasting. Amen and Amen" (41:13).
Sons of Korah, Asaph, David, and Solomon. Closes Book II — and, per its own closing note, David's contributions generally — with a doxology and the line "Thus conclude the prayers of David son of Jesse" (72:20): "Blessed be the LORD God, the God of Israel, who alone does marvelous deeds. And blessed be His glorious name forever; may all the earth be filled with His glory. Amen and amen" (72:18–19).
Mostly Asaph, closing with Ethan's raw lament over the apparent collapse of God's covenant with David — a psalm that ends in unresolved tension more than triumph, yet still closes on: "Blessed be the LORD forever! Amen and amen" (89:52).
Opens with Moses' prayer (90) and turns toward God's kingship over Israel's history, including a long recounting of the nation's repeated rebellion and God's repeated mercy in Psalm 106. Closes: "Blessed be the LORD, the God of Israel, from everlasting to everlasting. Let all the people say, 'Amen!' Hallelujah!" (106:48).
The longest book, containing the "Psalms of Ascent" pilgrims sang traveling up to Jerusalem (120–134) and the longest chapter in the entire Bible (119, an extended meditation on God's word). The whole book — and the whole Psalter — ends on an unrestrained command to praise: "Let everything that has breath praise the LORD! Hallelujah!" (150:6).
What kind of psalm are you reading? The major genres
Because the Psalter is compiled rather than argued, the single most useful question to ask of any individual psalm isn't "where does this fit in a storyline" but "what kind of poem is this." A few categories cover most of the 150:
Hymns of praise (like 8, 100, 145–150) simply celebrate who God is and what He has done, with little or no personal complaint mixed in. Laments — the single largest category in the book, both individual (13, 22, 42) and communal (44, 74, 79) — bring raw complaint, need, or confusion directly to God, almost always moving somewhere by the end. Thanksgiving psalms (30, 34, 116) look back on a specific answered prayer and publicly testify to it. Wisdom psalms (1, 37, 73) read more like Proverbs set to music, contrasting the righteous life with the foolish one. Royal/messianic psalms (2, 72, 110) were written for or about Israel's king, and are read by the New Testament as ultimately finding their fulfillment in Christ.
There's also a smaller, more difficult category worth naming honestly: imprecatory psalms (portions of 35, 69, 109, 137), which call down judgment or vengeance on enemies in unflinching, sometimes violent language. Christians who take these psalms seriously read them in real variety — some as raw, unfiltered honesty handed to God rather than acted on personally, some as a cry for justice from genuine victims of real violence, some as psalms whose New Testament fulfillment sits with God's judgment rather than human retaliation. Formation doesn't adjudicate that question here. What's worth noticing regardless of your view: even the harshest of these prayers is still addressed to God rather than acted out against the enemy directly — the anger goes into the prayer, not into a fist.
Worked example: Psalm 13, observed and interpreted
"How long, O LORD? Will You forget me forever? How long will You hide Your face from me? ... Consider me and respond, O LORD my God. Give light to my eyes, lest I sleep in death ... But I have trusted in Your loving devotion; my heart will rejoice in Your salvation. I will sing to the LORD, for He has been good to me." — Psalm 13:1, 3, 5–6 (BSB)
Observation: Six verses, three clear movements — complaint (vv. 1–2, four separate "how long" questions stacked back to back), petition (vv. 3–4, a specific, urgent ask), and praise (vv. 5–6, trust and song). Notice what doesn't happen between verse 4 and verse 5: no narrated event, no answered prayer described in the text, no circumstance change stated at all. The turn is not explained.
Interpretation: That missing explanation is the point, not an oversight. Psalm 13 doesn't model gratitude that follows a fixed problem — it models trust that outruns the available evidence. David's "how long" questions in verses 1–2 are not rebuked or walked back; they're allowed to stand fully voiced, and the pivot to trust in verse 5 happens anyway, on the strength of what God has proven to be ("Your loving devotion") rather than what circumstances currently show. This lament-to-praise pattern recurs across dozens of psalms (6, 22, 28, 30, 42) and represents one of the Psalter's core instructions about prayer: honest complaint and confident trust are not opposites that cancel each other out — they're sequential moves in the same act of faith.
Application: A fair question to sit with: in your own praying, do you tend to skip straight to verse 5 — the trust — because verses 1 and 2 feel like they aren't allowed? Psalm 13 suggests the complaint isn't a detour from faith; it's part of the route.
Study Psalms in Formation
Because Psalms rewards genre-first reading more than any other book, Formation's color-coding tools are especially useful here — tag every lament one color and every hymn of praise another, and the Psalter's actual shape becomes visible at a glance rather than staying buried in 150 undifferentiated chapters. Ask the Word's cross-reference mode can also trace a royal psalm like 72 forward into its New Testament fulfillment without losing your place in the text.