While this number is not completely confirmed it is said that 78 psalms were written by David and the other 73 of the 150 are by different writers. 73 Psalms are directly ascribed to him, and Psalms...
Traditionally, most of the Psalms are attributed to King David, although general tradition does not say when he actually wrote them. However, biblical scholars say that the Psalms were really written...
David is not normally accredited with any writings except the Psalms. Of these the superscriptions or titles (often with the occasion of writing) attribute 73 Psalms to him and the New Testament adds...
There is only one book of Psalms and King David wrote much of it. Some of the Psalms were composed by Adam, Shem, Abraham, Moses, and others. Please see the link below for more information.