Italian Rapier Fencing (Jared Kirby translation) by Ridolfo Capo Ferro.

The Book of Deeds of Arms and of Chivalry by Christine De Pizan (Sumner Willard translation).

The Inner Game of Fencing by Nick Evangilista.

Renaissance Swordsmanship : The Illustrated Use of Rapiers and Cut-And-Thrust Swords by John Clements.

And I just finished The Secret History of the Sword by J. Christoph Amberger.