From one of the reviews on Amazon:
Stone ruins in New Hampshire from the Bronze Age... Carthaginian coins on Mid-Atlantic islands... Phoenician inscriptions on rocks in Pennsylvania... Roman coins in Venezuela... rumors of bronze shields, daggers and swords... these are just a few of the clues which testify to the fact that many people came to this hemisphere long before Columbus!
In the tradition of the great mystery writers, the author of this absorbing book has woven fact, myth and theory into the adventures of nineteen groups of explorers, including Chinese, Irish, Vikings, Portuguese and Romans.
And maybe it's all true, but so what? Columbus "published" first, so he deservedly gets the credit. Hooray for Western Civ, and down with Islam.
Just like they teach that the Jews stole Israel from the Arabs.
The propaganda begins.
It could be said that Leif Erickson and the Indians landed in America, but Columbus discovered America for Europe and for us. Columbus is the one who's discovery is most significant.
Video of "The Enemies of Christopher Columbus, Cspan (over and hour long)