I had this book on my TBR for several months but only got to it after watching the first season of the TV series on BBC. The book is a detailed account of the battle for England in the late 800s between the Danes (Vikings, Norsemen, etc) and King Albert. The story follows Uhtred Ragnarson a Saxon who was captured by the Danes when he was 10 and raised as a son by Ragnar. Uhtred struggles with his upbringing as a Dane and love for Ragnar and the love of his ancestral home Brabbenburg in Northumbria.
Note for those interested in both the TV series and the book - The first season of the TV series extends beyond Book 1.