The author was Frans G Bengtsson, and he is depicted on this Swedish stamp together with typical Viking longships. The book, which is in several volumes, was written during World War II and Frans made a political point in the book on how the Vikings allied themselves with Jews over a thousand years earlier. He tried to simulate the language in the book after the old Nordic sagas, with their terse sentences and usually not very elaborate descriptions of people and places.
The 1960s movie Long Ships was partly and loosely based on this book, but I haven't seen it. But they are planning a real movie on the book now, and the director was quoted as saying "It will be like Lord of the Rings". Except of course that Vikings did happen. And Vikings had gold rings too, and there were smart women with long fine hair (but no pointy ears) not only in Tolkien's books. I hope they get a huge Hollywood budget to make this Viking movie.