Just finished Steven Pressfield's "Gates of Fire," a best-selling historical novel published in 1998, about the Battle of Thermopyle in 480 BC, the decisive battle in the Greco-Persian wars. It is a compelling story well-told of a fascinating period of history. An excellent read about an event that defines the word "epic".
It is, of course, the same storied event that was the subject of the popular movie "300" from 2006, by Frank Miller and Zack Snyder, although the book has a much different flavor, of course. I enjoyed the movie, as well, and I highly recommend the book. Here is a trailer for the movie: