A rather unique book in that it offers a history of exploration of the Americas before Columbus (hence the title, duh) from groups as varied as the Phoenicians, sailors from ancient Mali, the Welsh Prince Madoc, and of course the proven landfall of Scandinavians in the 1000s. Also included are the Irish, Chinese, and Basque.
Now personally I have little doubt that there were lots of people who visited the Americas before Columbus bumped into Hispanola accidently in 1492. Unfortunately, Wulffson's book does a disservice to these histories due to its telling of everything as fact (including some quite silly "discussions" between explores), as opposed a more nuanced view of offering these as possibilities, with little concrete historical facts to back up actuality (true this book is written at juvenile level, but still). The one funny thing about this book is the supposed Welsh settlement that existed here in Clark County at 14 Mile Creek in what is now Charlestown State Park.