From the Introduction,

In battle, the artillery has always had two roles. In defence, its purpose is to destroy the impetus of the enemy’s attacks, and in attack, its task is to destroy the enemy’s will to resist. Just that. And whether you consider the medieval wars or the Napoleonic wars or the great wars that followed them, those two tasks have remained.

– General Sir Thomas Lovett Morony, KCB, OBE, Master Gunner, St James Park (1985)

The author, Wen Jian Chung continues,