Who is Ardant du Picq from On Killing and what is their importance?

Ardant du Picq is a Frenchman. He was a pioneer in military science, conducting research that had never been done before. If it had been done, the methods had been less systematic and the results less reliabe. Ardant du Picq is cited repeatedly during the length of the entire book. Even if much of what he learned had already been known, it had not been well organized or presented to others as a body of knowledge.