By the time I was halfway through reading this again (I had read it a couple times in college), I realized that there was no way I could just write a single post about this work. It is just too complex. So, I am going to write a short series of posts on it. This is the first and I will update it with links to the subsequent posts after I get them written.
In his preface to the play, Shelley states that he drew inspiration from the lost drama of the same name by Aeschylus. Shelley uses the Prometheus myth to represent Satan as opposition to tyranny (symbolized by God/Jupiter) and as the champion of humankind.
The only imaginary being, resembling in any degree Prometheus, is Satan; and Prometheus is, in my judgment, a more poetical character than Satan, because, in addition to courage, and majesty, and firm and patient opposition to omnipotent force, he is susceptible of being described as exempt from the taints of ambition, envy, revenge, and a desire for personal aggrandizement, which, in the hero of Paradise Lost, interfere with the interest. The character of Satan engenders in the mind a pernicious casuistry which leads us to weigh his faults with his wrongs, and to excuse the former because the latter exceed all measure. In the minds of those who consider that magnificent fiction with a religious feeling it engenders something worse. But Prometheus is, as it were, the type of the highest perfection of moral and intellectual nature impelled by the purest and the truest motives to the best and noblest ends.
Throughout the play, Shelley asserts that love is the ultimate human emotion which will ultimately lead to the defeat of fear, tyranny, and oppression. Love is the energy which permeates everything in the world, and the highest goal of art is the expression of this universal love which will ultimately deliver humanity to freedom.
Shelley, in his preface, seems as defiant as Prometheus and Satan. He asserts that he would rather burn in Hell than bow artistically to Christian law.
For my part I had rather be damned with Plato and Lord Bacon than go to Heaven with Paley and Malthus. But it is a mistake to suppose that I dedicate my poetical compositions solely to the direct enforcement of reform, or that I consider them in any degree as containing a reasoned system on the theory of human life. Didactic poetry is my abhorrence; nothing can be equally well expressed in prose that is not tedious and supererogatory in verse. My purpose has hitherto been simply to familiarize the highly refined imagination of the more select classes of poetical readers with beautiful idealisms of moral excellence; aware that, until the mind can love, and admire, and trust, and hope, and endure, reasoned principles of moral conduct are seeds cast upon the highway of life which the unconscious passenger tramples into dust, although they would bear the harvest of his happiness.
In my subsequent post, I will look closer at specific passages which in my opinion represent some of the key issues in this drama. As I mentioned, this is a very dense and complex work, and I will not be able to cover everything, but I will do my best to hit some of the main aspects.