"Unquestionably the supreme kingship of Yahweh (in which he displays his transcendent greatness and goodness) is the most basic metaphor and most pervasive theological concept in the Psalter—as in the OT generally. It provides the fundamental perspective in which people are to view themselves, the whole creation, events in “nature” and history, and the future. All creation is Yahweh’s one kingdom. To be a creature in the world is to be a part of his kingdom and under his rule. To be a human being in the world is to be dependent on and responsible to him. To proudly deny that fact is the root of all wickedness—the wickedness that now pervades the world."Here is a great link to John Richard Sampey's article on Psalms in The International Standard Bible Encyclopedia online. I recommend it for your read. It helps to understand authorship, the psalm titles, the historical background and the various genres found in the psalter.