This book was published in 1961 and is a great summary of stories about people who may have come to America before Columbus. Boland was an amateur historian who took issue with the NEBC principle in American history. That is, No Europeans Before Columbus.
Boland sets out to question this idea and put forth as many proofs as he could find to point to why he believes there were many Europeans in America before Columbus, going back to the Phoenicians and Carthaginians. While Boland's style leaves much to be desired in terms of diplomacy, I appreciate that he not only recounts stories of past European visitors to America, but also took time to think about where these visitors went and what they did and their motivations for coming and other details.
As a reader of this book in 2013, I found that new evidence has come to light to corroborate some of Boland's stories like the Irish monks who went to Iceland before the Norse. Looking on the Internet, I found a story from 2011 about a professor from Wales who is researching man made caves in Iceland, now believed to be the dwelling places of these monks.
In his own time, Boland must have been heartened when Helge Ingstad and Anne Stine Insgstad, a husband and wife archeological team from Norway, announced their discovery of the archeological remains of a Norse village at L'Anse aux Meadows in Newfoundland. This was the first discovery of archeological evidence to corroborate the story of Norse voyages to North America around 1000 A.D, as told in the Icelandic Sagas. To this day, many consider L'Anse aux Meadows to be the only confirmed Norse site in North America outside Greenland.
Other stories like the discovery in Minnesota of the Kensington Runestone, which some believe was made by ancient Norse explorers, are still considered to be fraudulent. But who knows, maybe someday we will find new evidence to support these claims. In the meantime we have Boland to thank for compiling these stories and giving us ideas about where to look for evidence of Europeans in America before Columbus.