The Shaping of America: A Geographical Perspective on 500 Years of History: Volume IV: Global America (1915-2000) by D. W. Meinig

This volume begins by looking at the changes in technology (like the car and airplane) that changed American life, and then at the migrations within the country. It ends with American "missions"--that is U.S. involvement in the world beyond its borders. It chooses not to go into the changes that happened because of and after September 11. This volume, like the previous three, offers an entertaining and informative geography of the United States and indirectly makes a strong case for the viability of geography as a discipline.