The Book of Psalms is the nineteenth book of the Bible and the second book in the poetry section. The book is a collection of "Psalms" or songs written in Hebrew. The Psalms were all written under various circumstances, for different purposes and by different people. While the Psalms have a wide range of themes and purposes, they are all affirmed by the Holy Spirit.
A majority of the Psalms feature parallelism, where a repetition of a message is repeated (or contrasted) several times. One of the largest common themes in Psalms is trust of God no matter the circumstance.
There have been many authors that have contributed to the Book of Psalms as they were put together during Biblical times from the time of Moses to the Babylonian Exile. Known authors are King David, Asaph and his family, The sons of Korah, King Solomon, Moses, and Heman and Ethan the Ezrahites.
The literary style of the Psalms are written in what in poetry in a literary form called Synonymous Parallelism, which is when the main themes of the poem are restated in successive lines. Generally speaking The first half of a verse will make a statement, and the second half will essentially say the same thing in different words. The statements are “parallel” in that they are juxtaposed, or side by side, and they often share similar syntax.