individual psalms is organized into five books. Psalms is not a continuous, chronologically arranged story like we find in the historical books. Unlike prophecy, Psalms has no continuing message developed chronologically or thematically. And unlike epistles (letters), Psalms has no continuous unifying teaching or train of thought throughout the book. The book is an anthology—a collection of 150 different prayers, praises, or songs. Each psalm is a unit of expression, composed during a moment of need