The genre of Psalms is Songs and Poetry of all kinds. It is written by multiple authors; David wrote 73, Asaph wrote 12, the sons of Korah wrote 9, Solomon wrote 3, Ethan, and Moses each wrote one (Ps. 90), and 51 of the Psalms are anonymous. They were written over the span of approximately 900 years (Beginning at the time of Moses 1440 B.