The techniques of European warfare were transformed during the 15th and 16th centuries by the use of gunpowder and by substantial progress in the effectiveness and destructive power of artillery.The series of conflicts in the 1640s, known collectively as the English Civil War, was the first in the British Isles that reflected this new reality. Sieges that aimed at isolating and reducing fortified places became the dominant instrument for prosecuting the war and protective fortifications were vital, for both the besieged as well as the besieger.This illustrated guide describes how both the Parliamentarians and the Royalists made use of new fortification techniques throughout the course of this conflict.