It's not exactly a book; it's one of the first written stories to survive in the English language, kind of a long "poem" but in old English so you can't really understand it:

http://www.lone-star.net/literature/beowulf/

The text: http://classiclit.about.com/library/...eowulf-all.htm

It's really lousy reading, especially if you then have to discuss it as an older teenager in order to appear "educated" :-) My husband and I went to the same university so I know he had it in English also but he has blocked it from his mind, claims he's never heard of it, LOL; he was an engineering major.