Lots on incredible things in this book, especially if you only accepted the sanitized version of US history they teach in elementary and high school. They tend to get a little more realistic in college level courses in American history, thank goodness - but back to the subject at hand. Expect a lot of myth-busting, not just of any beloved or despised personalities (Andrew Jackson comes to mind), but of the ideals and attitudes we cherish about our country's growth into a true nation. One thing really helped my understanding of the period, and that's how the earliest period of the industrial revolution outweighed the "frontier spirit" of volunteer-supported armed conflicts of the period - and Howe makes the case for it at The Battle of New Orleans and 30 years later in the Mexican War.
It took a book like this to really make me understand how Spain's dwindling interest in its New World territories really gave the United States the opportunities it needed to expand from the Atlantic to the Pacific. There's no big coordinated 30-year plan to conquer North America - it happens in fits and starts.
While this book doesn't specialize in the Seminole Wars, the Texas War of Independence, or the US-Mexican War, the material in it gives the reader a good insight into the military-political perspectives of their origins, prosecutions, and resolutions. I picked up a softcover copy of the book pretty cheap from an online retailer (less than $15) - not a bad price for all the above, when compared to the price of an Osprey. Now if you really, really dig the era's zeitgeist, then this book is a fantastic value - there's got to be 800+ pages in it.