The most important part of Ferguson's book on the history of the Vikings is this caution to his readers: we really don't know very much. Our knowledge of the Vikings and their culture is severely limited; they left very few primary sources, and most of what we do know comes to us from, at best, a hundred years after the events happened, and narrated by Christians for whom historiography was more of an art than a science. There is much we can infer about these people, but it mostly consists of best guesses. In this book, Ferguson does his best to present to the reader the best of the best guesses, while also including differing theories and opinions so as to present a complete picture of possibilities.
The book is well written, though the first hundred pages goes much quicker than the last two. It could just be personal preference, but once Ferguson gets past the discussion on the religion and culture of the Vikings and gets into rote history, the narrative becomes rather dull. There are moments of wry humor, and Ferguson is, for the most part, an engaging writer, but facts presented as merely facts can only hold my interest for so long. The first section on religion and mythology, as well as the history of Viking archeology, was more to my taste. That being said, this is a solid, readable and approachable history of a fascinating people about whom we know too little, and I would recommend it to a lay reader looking to learn more on the subject.