Terry Brooks began his writing career with the 1977 Sword of Shannara this book was the beginning of a long and still ongoing fantasy series, the Shannara series. The successive series picked up steam with the overwelming success of Sword of Shannara. The follow up novels, Elfstones of Shannara and Wishsong of Shannara continue the successes and add depth to the post-apocalyptic world that Terry Brooks created with Sword.
The next series that began with Scions of Shannara tell the stories of the descendents of the Omsford family that saved the world multiple times in the originial three novels. Allanon's successor is found. The elves are saved. And the Border Lands unite to fight the Federation. The Shadoween and their hold over the Federation is vanquished and for a time there seems that there might be peace. The next series however, is the beginning of the end of Terry Brook's brilliance. The next series Isle Witch, Anthrax, and Morgawr tell the tale of the expedition to Park Asia and the airship The Jerle Shannara the crew is mostly destroyed on the foreign continent of Asia. Walker Boh the heir to Allanon's legacy never creates a new Druid order, but leaves it to his successor to do so. The next series of novels High Druid of Shannara series tells the eventual defeat of the Federation armies, and the outcome of the new druid order. This series is the final end to Shannra's fantasy brillance.
Each novel after the Voyage of the Jerle Shannra sereis has become shorter and more rushed. Instead of reading a 500 page epic like in the original novels, these novels have become shortened and condensed. The characters are often rushed with little to no development and quick deathes. The prequel novels add more questions to the formation of Shannra, such as the great wars and how America was nuked, when the insane soldier simply fired the NORAD missiles at foreign targets. America seems saved in the nuclear war that climaxed the destruction of Humanity.
America in the context of Bearers of the Black Staff is the world of Shannra or the beginning of that world that we see in the Shannra books, but many unanswered question with Armagedon's Children are left unanswered, such as how the United States became fragmented and how the landmass changed so much. No American nukes hit American cities, just foreign cities. While I can find it possible to imagine that Asia and Europe may have been forever altered, it is hard to imagein America in that state when most of the nukes didn't even hit North America.
In addition to the plot holes that have been created with the prequel novels, the creation of new races in America seem far-fetched, as there would not have been that many mutations without radiation. Instead of providing a series of novels that show the great wars and the nuclear war that was told in the original novels that destoyed the world, Terry Brooks decides to rip apart his own lore and retcon it. A trend I am finding more and more familiar with my favorite books and video games. While I believe Terry Brook's books up until The High Druid of Shannara series are great reads, I find that his successive novels to be full of plot holes, rushed characters, and uneventful stories in general. If you want to read a good Shannra book, pick up Elfstones of Shannra.