The book of Psalms is a collection of songs (poetry) of the Hebrew people. It boasts a multitude of authors over many centuries, some unidentified, though many are attributed to King David.
There are three basic styles of Psalms: hymns of praise, laments, and songs of thanksgiving.
Some Psalms mention not only the author but also the time or circumstances under which they were written. Others even include musical notations and names of tunes, both of which have little significance at this time.
Many people adore the Psalms, while others remain unaffected. In English translations, the wording often tends to be smooth and flowing, while in Hebrew they come out as more worldly and rough. The Message version of the Bible best captures the original intensity of Psalms.
Interesting trivia: Psalms has more chapters than any book of the Bible (150 chapters) and has the greatest length. It also contains the longest chapter (Psalms 119), as well as the shortest (Psalm 117). The oldest Psalm was written by Moses (Psalms 90). Psalms is frequently quoted in the New Testament (the other most quoted books are Isaiah, Deuteronomy, and Genesis).