Early gunpowder weaponry

I've unaccountably developed an interest in early gunpowder weapons. I've got Hall's Weapons and Warfare in Renaissance Europe and de Vries and Smith's The Artillery of the Dukes of Burgundy.

I'm eyeing Chase's Firearms: A Global History to 1700. Anyone read it? Other suggestions?

Nope, but sure would like to find out the consensus on the first battle that a gunpowder weapon was use (in Europe). And if there were indeed gunpowder weapons at Crecy and later on Agincourt.