The Creation of the American Republic, Gordon S. Wood

Heavy stuff, Gordon. You must be a professor or something. But really, to get a sense of the ideological evolution of American politics before the Constitution was written, this might not be the best place to start. It's written for elitist post-graduates; you know, the kind of book that purposefully tries to confuse undergraduate perfectionists and drive them crazy, so they'll follow up the readings with an agonizing amount of research, score poorer on papers, and be more miserable in general. It doesn't explain things the way a formal textbook would, as it assumes you already have a strong foundation on post-Revolutionary knowledge. However, if you're experienced in history or difficult literature, this might be one of the amazing books you'll ever read. Wood has a superior prose, the best of any historian I've read. Even if his topics tend to go on and on, all 500 some-odd pages flow with the elegant consistency of a gifted writer.