Do keep going through to Book XXII --the account of the Battle of Trasimene is absolutely some of the best Latin prose I have ever read. The lead-up feels like some big, epic movie: the sheer things the man does with language should be illegal, they're so good. Gosh, I need to read it again because I get chills just thinking about it -- there's a bit, the line just before the battle starts, and I won't spoil it for you, but when you get there, pay attention to the meter in your reading because what he does with the clausulae there is utter perfection. If ever an author's style was inspired by the divines, it must be Livy.