National Geographic published some longer, generously illustrated non-fiction picture books, and this is one of them. A great aid to any homeschool's History curriculum. We have picked up several different titles from the library like this one. I, for one, learned a lot! From their site:

This entertaining saga brings a legendary land deal to life. Over 60 reproductions of art from the period, a cast of characters, maps, a timeline, endnotes, a bibliography, and index give young readers all the resources they need to understand the period in which the Purchase took place.