Azincourt by Bernard Cornwell

Cornwell's tale of the Agincourt campaign follows the career of a longbowman who gets made ventenar (sergeant in command of twenty archers) during those events. As fans of Cornwell may expect, he has a some diabolical enemies - some English, some French - who he crosses paths with on and off during the course of the novel. The times are brutal, and so is the story, especially his many little revisionist takes on the romanticized version of the story (e.g. Shakespeare's).

Most importantly, contains all the adventure and historical detail that you would expect. Great stuff.