I’ve recently finished reading the Horus Heresy, a 64-book series set in the world of the tabletop wargame Warhammer 40,000. In reflecting on the series, and the theme of scale, I’ve written three summaries at different lengths:

The Horus Heresy in 100 Words

The Horus Heresy in 500 Words

What Actually Happens in the Horus Heresy?

Here I want to give some context for those summaries, and maybe talk a little about the Heresy as a whole. To start, we should acknowledge that the Horus Heresy is an absolutely mammoth piece of work. The series has been created by a stable of a dozen plus writers over eighteen years. The first novel, Dan Abnett’s Horus Rising, came out in 2006. The final novel, The End and the Death, volume III, came out in January 2024. There are 64 books in the series as a whole, plus a bunch of unnumbered supplementary short stories and novels. It’s an enormous undertaking. Across the 64 books we have a total 28,704 pages – if we’re averaging about three hundred words a page, it’s something in the realm of eight and a half million words. It’s roughly seven times the length of In Search of Lost Time, or double the total word count of Charles Dickens’ entire collected works. There’s nothing else like it. It’s a wildly ambitious project, with near-incomparable scale. And it’s all one story.

That scope in itself poses some really interesting questions. For the writers, there are logistical issues, practical problems of canon and maintaining continuity. How do you make sure you’re up to date with all the relevant characters and story arcs? A lot of the Heresy writers have a background in comics or other serial forms, so they’re used to these sorts of problems – but it’s probably less common to see them in the context of the novel, which is a much larger canvas. There’s a big difference between a 20-page comic and a 90,000-word novel. For the readers, there’s also a question of – how do you make sense of this? How do you make meaning out of something so huge? How do you process it all – how do you actually think about a story on that scale? When you’re reading the fiftieth novel in a series and they’re introducing yet another set of new characters, how do you invest in them? How do you understand the meaning or significance of their lives, their value in the grand scheme? Where do you find it in yourself to care? Wouldn’t you eventually give up on their humanity, let them fade into this noisy wash of places and names? When you’re meeting Captain Splurgle of the 309th on the planet Zim Zom – as a reader, isn’t there a point where you just stop caring?

That in turn becomes a thematic question for the series as a whole. Warhammer 40,000 is about a future of total war – unimaginable scale and countless human lives all wrapped up in violence and conflict. In the boilerplate for Warhammer 40,000, the sort of standard text inserted at the start of every novel, we read that a thousand lives are sacrificed every day to keep the Emperor alive. A thousand people every day – that’s too many to care about. There isn’t the time in the world to dig into each of those individual lives. You wouldn’t ever be able to know them all – certainly not before the next day’s sacrifices roll in. Warhammer 40,000 is about the dehumanising effects of life at scale. It’s about how the individual human story is lost under the weight of statistics. It’s about the horror of the city, the horror of large populations. Warhammer’s quintessential backdrop is the hive world, where billions of people are packed into world-spanning megacities. The emotional problem for the reader – how do you bring yourself to care about a new bunch of characters in yet another Heresy novel – is a thematic problem for the series as a whole. The series wrestles with the concept of empathy in the city. People suffer and die around us every day, unnamed, unknown, interchangeable. What does it mean to be a human in that context?

For all of those reasons – the logistical challenge, the scope of the achievement, and the pairing of theme and format – the Heresy has been a focal point for me for three and a half years now. I’ve read all sixty-four books since January 2022, either in hard copy, ebook, or audiobook, and I’ve written a dozen essays under the Horus Heresy special project. The final pieces, now falling into place, include these three summaries of the Horus Heresy. As a series about scope, about scale, it made sense to write about the Heresy at three different lengths. The first summary is in a hundred words, the second in five hundred, and the third a little under four thousand. Really that’s one of the most shocking things about the Heresy – for a series with such breadth, you can sum it up pretty simply. The Horus Heresy is a fall of Lucifer tale where Horus rebels against his godlike father and is cast down and slain. That is the point of the needle, the zero-point of the singularity. Sixty-four books, one sentence. That simple description unfolds into millions of words and thousands of characters. All of the bullets and bolter shells and lasguns and fear and hope and violent deaths, manifested across dozens and dozens of books, all hurtle out of that simple, archetypal structure. A son rebels against his father, and the whole galaxy burns.

The narrative overall shuttles back and forth between that very personal, intimate level and the sweeping vista of the entire galaxy. In the final novel, The End and the Death vol III, there’s a line where the nascent saint Euphrati Keeler proclaims a link between the people of the Imperium and the body of the Emperor: “Who are we fighting for, if not them? To safeguard the people is to safeguard the Imperium, and to protect that is to protect the Emperor Himself. Our citizens are the body of the Emperor.” It’s a Biblical theme, most strongly developed through 1 Corinthians 12: “For by one Spirit we are all baptised into one body … now ye are the body of Christ.” As in The Solar War, the body is a cosmic body, a galactic form. The struggle of the individual is the struggle of the archetype, a manifestation of the cosmic battle in each small and otherwise incidental moment. It is a repeating pattern, a wave that sweeps across the series, giving shape and structure. Shuttling, then, seems like the most appropriate form of summary. Offering only something short or only something long misses the underlying movement of the Heresy as a whole. It’s both. If it was only the granular action, the series would devolve into an endless list of places and names – a tired, boring parade. If it was only the high level, the conceptual framework for the conflict, you would miss the actual sequencing of events, the progression of the war across the scope of the series. The one sentence summary is great in an elevator, but it doesn’t give you time to talk about Lorgar.

And that’s not to say that the Heresy is always perfectly paced, or that it’s uniform in quality. I’ve been very overt about what I see as the series’ flaws. Some of it drags, some of it’s poorly written, some of it feels padded or wastefully inconsequential. But the superstructure always adheres to this process of shuttling between different scales. There is probably still a pending question about exactly how you mark those scales – I’ve offered a 100-word and a 500-word summary partly to recognise the distinction between the summary by archetype and the summary by acts. That is, the 100-word summary gives an overview of the ‘fall of Lucifer’ archetype, while the 500-word summary spells out the rough three-act structure of the series as a whole. You could also argue that the long summary could go into more detail. What’s the difference between a summary of 4000 words and one of 8000? There’s definitely a bunch of stuff I didn’t mention in the long summary. I didn’t talk about why Lorgar wasn’t at the Siege of Terra (he got banished at the end of Slaves to Darkness for trying to mind-control Horus), or the role of the Dark Angels in defending the Astronomicon during the Siege of Terra. There’s always more detail that could be offered.

Really I tried to focus on what felt like a readable length, and particularly making the broader piece flow. I tried to focus on closure, mapping things that happen at the start to things that happen later (like Mortarion trying to tempt Jaghatai in Scars, and then their final duel in the Siege of Terra). I also stayed away from certain terms and labels that I just don’t think are that important. Events like the Binary Succession and the Thramas Crusade are important touchpoints within the lore, but they don’t really matter to this narrative. And some peripheral books also have their own existence, with little connection to the Heresy’s main threads. Damnation of Pythos doesn’t do all that much to move the story forward. The Outcast Dead is similarly tying up a loose end. Both of these books have their own integrity as stories, and I think they’re fairly good, but they aren’t that central to the arc of the Heresy. In short, what I’ve mapped (or tried to map) is the arc of the Horus Heresy as a narrative unit, as a collection of sixty-four texts, rather than in terms of the events that happen in the fictional world. Consequence to the story was more important than consequence for the lore.

That’s really at the heart of my work here: whatever else the Heresy is – spin-off novels for a wargame, an alternate revenue stream for Games Workshop, a formal codifying of the sprawling, irregular lore scattered across forty years of codexes and rulebooks – it’s also a narrative unit. These are, now, books. They’re a science fiction series. They have themes and plot, and they sit together as a narrative work. We can treat them as such. We can read them, analyse them, piece together their themes and overall structure – and to some extent, we can do that independent of anything else. The Horus Heresy series, as a unit, is here completed. It doesn’t depend on all the other stuff – all the baggage, all the other extant material or the material yet to come. It’s not disconnected from the wider 40K universe, of course, but it’s been given to us as a complete series. It has its own integrity and fullness. The whole of the Heresy is here, in these sixty-four books, as a fixed and stable point. There’s always going to be other stuff, other pieces added on and expanding on the lore – that’s not what I’m talking about. The tales and legends will continue to grow, but the Heresy series exists now as one complete and total unit. It’s finished, and we can appreciate it in its entirety. It’s a staggering achievement.