Introduction. For the last few thousand years, wars have been fought with weapons.

For the last few thousand years, wars have been fought with weapons.

For long stretches of time, they have been fought with the same, or similar, weapons. For example, flintlock smoothbore muskets were the basic infantry weapons for more than a century. When, in the early 19th century, they were replaced by percussion smoothbore muskets, soldiers got a more reliable weapon, but they didn’t have to change their tactics. A little later, they were given percussion rifled muskets. The musket looked almost the same. It had a percussion lock, and it was a muzzle‑loader. About the only difference was the rifling grooves in the barrel. Generals didn’t see why they should change their tactics. That’s why the American Civil War is the bloodiest war in our history.

Most of the weapons that change warfare eventually become obsolete. The weapons that replace them may further change warfare, or they may not. The muzzle‑loading rifle was quickly replaced by the breech‑loading rifle, and the breech‑loading single‑shot by the breech‑loading repeater. The repeater let troops fire faster. The muzzle‑loading rifle had taught infantry the need to disperse and take cover. The breech‑loader made firing from cover much easier, which meant that infantry opposing it had to move faster and in smaller groups. That was a substantial change. When the repeating rifle replaced the single‑shot breech‑loader, soldiers could still fire from cover, but they fired much faster.

That should have required infantry opposing them to move faster and in smaller groups. Troops in the Second Boer War and the Russo‑Japanese War learned that the hard way, but most European generals at the beginning of World War I hadn’t even learned the lessons of the American Civil War. But then the machine gun appeared as a major weapon. In World War I, Hiram Maxim’s brainchild demonstrated that tactics needed a drastic revision. The machine gun is still with us, but thanks to the tank it no longer owns the battlefield. The tank and its aerial partner, the dive bomber, took over ownership of battlefields early in World War II, but the “blitzkrieg” they created was quickly countered by other new weapons such as antitank land mines and shaped‑charge rockets and artillery shells.

One war‑changing weapon that did not become obsolete was Greek fire. In the 7th, 8th, and 9th centuries, it was the ultimate naval weapon. Then it was lost. It didn’t get a chance to become obsolete. While it was in use, though, it preserved the life of the Byzantine Empire, which profoundly changed the history of Europe, and the history of the world.

Most weapons that changed war were used over a long period of time. One was used only twice, but it has changed the way people thought about war and waged war for a long time. Whether nuclear weapons will continue to have this effect cannot be predicted, although it is certainly hoped for.

This book will look at how 50 weapons changed war in much the same way as my previous book, 50 Battles that Changed the World, looked at the most important military encounters in history. Each of the following chapters will explain how the weapon in question changed war, usually through showing how it was used in battle. It will also describe, in easy‑to‑follow terms, how the weapon worked. The weapons are presented in roughly chronological order –

roughly because, with many weapons, it’s difficult to say exactly when they went into use. Not all are like the tank, the introduction of which can be pin‑pointed at September 13, 1916. Bows and arrows were in use by 9000 BC and probably had been invented thousands of years prior. And even with tanks, there are qualifications. They are the most powerful of a larger class of weapons: armored vehicles. Armored vehicles go back at least as far as the Hussite Wars of the 15th century. But when we discuss armored vehicles, we’ll start with World War I, because that was when they began to permanently change warfare. The same is true of armored ships, which were first used by the Korean admiral Yi Sun Shin in 1592. Yi’s armored ships foiled a Japanese invasion, but they played no further part in warfare. So we start our discussion of armored ships – which include cruisers, battleships, and aircraft carriers – with the era when the C.S.S. Virginia and the U.S.S. Monitor revolutionized naval warfare.

Their records of making major changes in warfare was the reason these 50 weapons were chosen. For instance, the revolver is one of the weapons listed but the semiautomatic pistol is not, although most modern handgunners agree that the “automatic” is a more efficient weapon. The reason is that the revolver permanently changed cavalry fighting, but by the time the semiautomatic pistol was perfected, cavalry had become obsolete.

At the end of the book, I’ve included a list of “honorable mentions,” weapons that didn’t make the list of the 50 most important, with explanations as to why they were not chosen.