When Brett Devereaux wrote his Fremen Mirage posts early in 2020 I made some notes about warfare between Great Houses in the Dune books. The release of the trailer for the new Dune movie inspired me to turn these into something more organised, and in April 2025 I added some extra notes after online discussion.
Warfare in Dune, the first three books in particular, is unusual in science fiction. Many science fiction books, and every movie or TV show I've seen, depicts future warfare as an extension of the 20th century. Ground forces are disciplined infantry and armoured fighting vehicles with high velocity projectile weapons or some kind of laser. Spaceships fight like battleships or aircraft carriers depending on the writer's preference as to how the tech tree develops.
Dune has aristocrats and their retainers fighting hand to hand with swords and knives. Ornithopters (light aircraft that have flapping rather than fixed wings) act as troop transports and for reconnaissance, but don't engage in dogfights. Spaceships are also just for transporting troops and don't fight each other. It's all very medieval.
And this seems to confuse or upset the authors who have extended Dune with new books or written scripts for movies and TV. The Prelude to Dune series of books by Frank Herbert's son and Kevin Anderson have lots of laser fire and battles in air and space. The first Dune movie and the SciFi channel miniseries likewise had energy weapons and guns. Can't be science fiction without lasers, right?
Which to me is very disappointing. Science fiction at its best asks how we'll change and do things differently, not just linear extrapolation from now. Why do the Great Houses of the Imperium in Dune fight the way they do?
This discussion is focussed on the first three books: Dune, Dune Messiah, and Children of Dune. The Dune universe changes dramatically after that, and warfare does too.
I'm not going to analyse in too much detail how the weapon systems work, because that's already been done by Daniel Duffy. In particular, I'm not going to question whether the science and technology of Dune are actually possible. This is an in-universe discussion, accepting that Holtzman fields and the other gadgets all work as described.
My argument is that Dune warfare can only exist because of three factors:
Shields, the defence against projectiles and lasers.
The Butlerian Jihad, the prohibition on artificial intelligence.
The Imperium, the aristocratic ruling class that controls society.
Take away any of these and the distinctive style of warfare in Dune would no longer be practical.
In Dune these are a Holtzman force field used as defence. A shield can be set to block any moving object above a certain velocity. This works in both directions, so a shield that stops bullets coming in also stops you from shooting out.
Shields are usually personal, protecting one individual. A personal shield is a little gadget, about the size of a mobile phone, and you activate your shield by pushing a button. Once activated, only slow moving objects can pass through the shield. (It is not practical to tune the shield to block all moving objects, because that would stop the movement of air molecules in and out of the shield and you would suffocate inside it.)
Shields are also common on vehicles, for example ornithopters. Entire buildings can be shielded, such as the Ducal palace on Arrakis, and also building sized spaceships on the ground, but this seems less common. There seems to be a scaling effect making large volume shields much more expensive.
Shields are the ultimate in knightly armour. Warriors with shields are immune to all the missile weapons that defeated knights historically. With no longbows or muskets or machine guns, shielded infantry must fight each other hand to hand and skill with melee weapons is all important.
For the same reason there are no tanks in Dune, no heavy artillery, no ground attack helicopters or bombers. Big guns are no better than hand held guns, so vehicles are only useful to move infantry around. On Caladan and Arrakis ornithopters are superior to ground transport, but other planets might use light wheeled vehicles as infantry troop carriers.
The books do suggest that shields don't protect entirely against very powerful kinetic impacts. In the deserts of Arrakis shields are useless, because sandworms will kill the wearer. So it is possible to collapse a shield with enough force, or maybe just bounce it around so hard that the person inside is injured or killed like an egg inside an unpadded box. But sandworms are big, really big, suggesting that the amount of kinetic energy required to kill one shielded warrior would be at least an entire salvo of battleship guns.
Melee weapons
Shields are the perfect defence against projectile weapons, from thrown rocks to bows to guns to artillery. They also reduce the effectiveness of many historical melee weapons.
Impact weapons such as clubs, axes, maces all rely on being swung fast. Two handed swords and polearms are likewise long because the tip is moving faster and thus more damaging. Neither will work against shields.
Long stabbing swords and spears would still be dangerous, but if you can't make a quick thrust an opponent can easily dodge or push the point aside and then step in closer, leaving you helpless. This was a standard historical technique for sword vs spear, or short sword vs rapier, and in the Dune Imperium it would be even easier. However, as seen in Villeneuve's movie, spears might be useful for infantry in close formation, as the multiple points would form a barrier that would be harder to get past.
The best weapons for shield fighting would be those that can be moved slowly and precisely through the shield, not long enough to give an opponent much leverage at the tip, and still lethal with short hand and arm motion. Hence short swords and knives with both thrusting point and cutting edges.
Lasers
Lasers, called lasguns throughout Dune, are a special case. Firing a laser at a shield creates an explosion, and feedback, reflected energy of some kind, destroys the laser as well. Worse still the explosion is unpredictable, it might be equivalent to an artillery shell, or it might be equivalent to a nuclear bomb.
(No, I have no idea why. It's science fiction, and I'm accepting that in the universe of Dune this it what happens. Perhaps visible light / EM radiation always generates some feedback, but without the coherence of a laser beam it is too scattered to be harmful.)
Gamers of a certain type ask why Dune doesn't have people trading off one lasgun operator for many enemies. This misunderstands the purpose of warfare, which isn't just to blow things up. If a Dune Great House is invading another, the goal is to capture valuable people and stuff, not destroy it all. If you are defending against an invasion, you'd like to have more than rubble left when you beat back the attackers. At the personal level, if a shielded assassin is trying to kill Baron Harkonnen, shooting the assassin with a laser might save the Baron's life, but will kill everyone in the vicinity who isn't wearing a shield and convert the Baron's palace into a crater.
There is an additional danger from causing a possibly atomic level explosion. The Imperium of Dune does have atomic weapons, but like our world relies on mutual assured destruction: the Great Convention states that anyone using atomic weapons against other human beings will have their entire home planet destroyed. Even if the explosion was technically caused by a lasgun - shield interaction rather than a true atomic weapon, or was not intentional, the entire political structure of the Imperium does not want wars to be fought like this and so will nuke the offender anyway.
(Yes, Duncan Idaho in the first Dune book plants a shield to be set off by pursuing Harkonnens. The Atreides have already lost by this point, he can't make things any worse. He also knows that with the Sardaukar being involved the Harkonnens won't want any kind of investigation.)
So lasguns are too destructive to be practical weapons in combat, and the Imperium as a whole will retaliate against anyone who uses them as weapons of mass destruction.
Body armour
Dune shields are the equivalent of having the USS Enterprise shields as an app on your phone. In D & D shields would be AC 20. Any medieval knight would swap full plate armour for a Dune shield in a heartbeat. Yet despite being better protection than any armour in history, people still ask why soldiers in Dune don't wear body armour as well.
They don't because protection has always been a tradeoff. Too much armour decreases the ability of a soldier - or a tank, or a battleship - to be effective in warfare: you don't win just by being better protected. For soldiers in Dune body armour would be time consuming, heavy, hot, and encumbering; disadvantages that outweigh the relatively slight increase in protection.
Body armour takes time to put on, fifteen minutes or more, and usually requires some help from another person. A shield is activated by pushing a button. You don't want your soldiers caught by surprise while they are in the middle of putting on their armour.
A good suit of body armour weighs twenty kilos or more. This means your soldiers carry twenty kilos less of water, less radios or other equipment.
Body armour is hot. Your soldiers won't be able to walk, run, or fight for as long as those with shields only. (Contrary to many RPGs you can still run quickly in well fitting armour, but it is more tiring and it is harder to turn or stop.) Combat is exhausting, combat in armour even more so.
Body armour is encumbering. It's harder to duck, bend, jump in armour. Gauntlets, armour for your hands, are especially bad for soldiers who may need to push buttons, drive vehicles, operate radios.
Helmets in particular interfere with hearing, vision, breathing. Soldiers need to hear commands and warnings and other sounds around them. They need to see where they are, what their allies and enemies are doing. And they need to breathe in a lot of oxygen because, again, combat is exhausting. We know that historically even very rich medieval nobles wore open faced helmets in battle, despite the risk of being shot in the face.
(In the Villeneuve movies I think armour is worn to visually distinguish soldiers from civilians. From ancient times until firearms became dominant soldiers going into battle wore armour. For a few centuries until the late 20th soldiers wore just helmets, but here in the early 21st C we, at least in the industrialised world, expect to see soldiers wearing body armour.)
This is, by the time of Dune, the long-ago crusade against machines that think, or as perceived as being capable of performing similar functions to the human mind. It is a thoroughly ingrained moral and religious prohibition. So the Imperium has no computers. No autopilots or homing missiles or autonomous drones.
(It's hard for us in the early 21st century to imagine why large numbers of people would obey or enforce such a ban, but consider the example of slavery in how attitudes can change. Slavery was accepted or even expected in most of the world for thousands of years, but then in the space of just a century or two was outlawed across the globe. Any remnants of slavery today have to be kept secret.)
This prohibition prevents some possible weapons that could be used against shielded fighters. In Dune, the Harkonnens try to assassinate Paul with a tiny flying poisoned needle, remotely piloted. With artificial intelligence, even in the limited computer forms of today, these would be deadly. Flood the battlefield with artificial poison wasps, each with an on-board computer that searches for a target and adjusts its speed as necessary to penetrate the shield.
A second example is from Dune Messiah. Alia trains against a mechanical / electronic sword fighting "target" which could kill her if she makes a mistake. With AI these could become the Terminators of Dune.
(That this training robot even exists suggests that the most privileged members of the Imperium can ignore the Butlerian Jihad prohibition to some extent, provided they don't get caught. During the reign of the God-Emperor Leto II we learn that computers are used by his highest ranking household, and the Bene Gesseret apparently used computers to manage their breeding program from the beginning.)
So computer AI-powered weapons are technologically possible in Dune, but any widespread use of "smart" weapons would provoke a massive counter reaction. Such weapons might win you a battle, but then you and your Great House would get wiped out by a religious crusade, likely including members of your own army and/or population.
Without AI the flying poison needles would be very labour intensive, each requiring a human pilot. Still, the ability to kill your opponent without needing to be close enough for them to hurt you has always been appealing, so why aren't these in use on battlefields as well? Which leads us to the third, equally important factor.
What is necessary and what is acceptable in warfare always depends on the society, economy, politics. The Dune Imperium is hierarchical and aristocratic, ruled by an Emperor and noble Great Houses.
These are not nice people. Frank Herbert himself was well aware of this, pointing out in an interview that Leto Atreides may be benevolent, but he's still an absolute dictator. The Atreides on Caladan and then Arrakis may be good rulers, but not because there is a requirement or obligation to be so. The Harkonnens are not breaching any Declaration of Human Rights with their atrocities and oppression.
Melee combat, armour and swords in our history or Holtzman shields and swords in Dune, is a style of warfare that favours the rich and privileged who can afford quality equipment and have time to train. In the Dune Imperium the nobles and their personal retainers will slaughter a much larger number of unshielded or poorly trained fighters.
It is said that during the medieval Hundred Years War between England and France, the King of France wanted to teach the commoners to use longbows like the English. This was blocked by the French nobility, who knew that French longbows could just as easily be used against them once the war was over. Whether this actually happened doesn't really matter. The medieval writers recognised the conflict of interest, and this same conflict is present in Dune. The current style of warfare benefits the emperor and nobles. They have no motivation to overthrow the system that makes them rich and powerful, and thus no reason to fund or support research and development into new weapons or tactics. They are however strongly motivated to crush any upstart or outsider looking to innovate.
As with so much of Frank Herbert's Dune books, it's not the technology, it's the sociology and psychology and human nature. The ruling class of the Imperium are, collectively, well aware that shields are not unbeatable and there are other ways to fight. They don't want to change.
The frozen structure of the Dune Imperium, and its unique style of warfare, lasts for many thousands of years.
Fortunately for humanity as a whole, the Imperium is overthrown by Paul Muad'Dib. The Golden Path of the God-Emperor Leto II then destroys the remnants, and the Scattering after his death creates new external enemies far more dangerous than the English were to the French.
Frank Herbert himself recognised that shields and shield warfare is only sustainable within a particular social structure. In his last two novels Heretics / Chapter House of Dune warfare has become very different. Shields are considered obsolete, and when brought back are not for defence, but as the equivalent of explosive mines and traps. There is combat in space, and armies use computers. Ground and air warfare uses long range weaponry and armoured vehicles. Combat is now on a larger scale and more destructive. Warfare has become more democratic, more industrial, and in the universe of Dune this is an improvement.
There are many Dune books, and many more non-fiction books and articles about Dune. Here are some of the most interesting for this topic.
An Analysis of Warfare & Technology in the Dune Universe Daniel Duffy
The Fremen Mirage Bret Devereaux
The Problem With Sci-Fi Body Armor Bret Devereaux
Frank Herbert Tim O'Reilly