For most of the last century, historians have all but ignored the role of artillery in the English Civil Wars. Scholars have dismissed seventeenth-century cannons and mortars because they were considered to be too small and inaccurate, as well as too few in number, to impact any major battle of the wars. Stephen Bull takes issue with this interpretation. He argues that Civil War–era cannons were numerous, that their accuracy and the quality of their ordinance was essentially the same as the guns used in the Napoleonic wars, and that the state spent huge sums of money on the guns and the fortifications designed to defend against them. In short, Bull asserts that artillery was a major part of war planning, war expenditure, and a key factor in combat in both open field battles and sieges. Thus, in order to understand the course of the Civil Wars, we must appreciate the role artillery played in them.

Bull devotes the first two chapters of his book to explaining how mid-seventeenth-century cannons actually worked, how they were made, who built them, and where they were located throughout the country. The English government considered there to be eight or nine major categories of guns, although there were many guns that did not fit into its rubric. These guns ranged in size from quite large, so big they were set on wheels and pulled by a team of horses, to those that were so small they could be disassembled and transported on the back of a pack animal. When gunners fired the ordinance, they usually used cartridges, which were made out of paper. When they lit the charge and it exploded out of the gun, the rate of travel was 1,500 feet per second, which is roughly the same speed at which bullets explode from modern firearms. The guns were pretty accurate up to 700 yards, although this very much depended on the skill of the gunner and his familiarity with the particular gun. The shot, which could literally be a single ball or many small pieces of shot, was incredibly destructive. A well-placed shot could bounce through several different groups of advancing enemy forces, causing havoc and inflicting terrible injuries. Further, the guns were quite dangerous to the men firing them, and many gunners were hurt or killed by their own ordnance. One of the highlights of the book is Bull's description of the noise of the guns. Reminding the reader that the seventeenth century was a much quieter place than the modern world, Bull recreates how the noise of a firing gun would likely be the loudest thing, short of thunder, that any person at the time would ever hear. It could not help but be impressive.

Most of this ordinance was built by the Browne family, who by the 1630s had almost a monopoly on artillery production in England. For instance, when the Navy placed a major order for cannons in 1638, the Browne family manufactured and sold the Navy ninety-six guns while their leading competitor sold the Navy only six. One of the reasons the Browne cartel did so well was because it was based in the southwest, and the government preferred to keep the majority of its weapons in and around London. Of course, it did have other stores of them spread throughout the country. These caches, Bull argues, shaped the strategies of both sides in the opening months of the Civil War in 1642. In fact, he notes that through August 1642 the aim of both the Royalist and Parliamentary forces was to secure guns, powder, and shot. Once fighting began, financing the various demands of the artillery units was a major concern for both sides. Here, Parliament far outperformed the Royalists because it controlled the major production areas and had more money to spend on ammunition. Often the Royalists had to purchase second-rate guns from overseas, use guns that were 100 years old, or try to steal them from their domestic opponents.

To defend against these pieces of hardware both sides spent tens of thousands, if not hundreds of thousands, of pounds building fortifications around cities and towns. There were three major types of fortifications: new ones, those grafted onto existing medieval fortifications, or a series of forts. Some of these defenses were in almost constant use, while others were erected and never faced fire. In any case, Bull maintains that the enormous effort spent in building and paying for these fortifications demonstrated that contemporaries believed that defense against artillery was one of their most important security problems.

Bull spends the last two chapters of the book describing the use of artillery in sieges and in open combat. He provides an impressive string of examples that reveal how it was used to batter down walls, how the different armies deployed it in the field, and its pivotal role in some of the most important battles of the war. This book, while admittedly narrow in scope, is a very useful reminder that for those involved in the Civil Wars, the ordnance, in all its fury, was incredibly important.