- There are a lot of states and a lot of capital cities, all of which consider themselves separate and unique under one umbrella.
- There have been a lot of wars and conflicts, internally and externally: turmoil between north and south, fights between states and federal governments, conquests of local inhabitants by those moving in to take over, and fights around the world for philosophical and political reasons.
- People come from everywhere but once they're in the US, they consider themselves American and try to keep others from changing their own luck.
- Americans value independence and DIY. They like to solve problems and move forward.
So a middle-school book summarizing the history of the USA is a treasure - an overview and not too much complexity. There are enough details to tie things together and enough research to make sense. Written by scholars to augment the classroom, it's both interesting and informative.