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Is Eisenhorn: Xenos worth reading? Yes — if the Horus Heresy is the best way into Warhammer’s past, Xenos is the best way into its present. Dan Abnett’s 2001 novel introduces Inquisitor Gregor Eisenhorn, gives you a grand tour of the 41st-millennium Imperium from the ground up, and reads like a propulsive noir thriller while it does it. For many fans it’s the first 40k book they ever loved.
This review is spoiler-light. For more starting points, see our best Warhammer books guide.
Where to Buy Eisenhorn: Xenos
Our pick of edition: Xenos – Eisenhorn Book 1 (Kindle edition).
Price details
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What is Xenos about?
Xenos follows Inquisitor Eisenhorn, an agent of the Ordo Xenos, as a routine hunt for a heretic unravels into a conspiracy that threatens far more than one world. Told in the first person, it’s part detective story, part horror, part interstellar chase — Eisenhorn interrogates, investigates, and fights his way across worlds, gathering a memorable retinue as the stakes escalate.
What makes it special is the vantage point. Where much 40k fiction follows Space Marines, Eisenhorn is a (super-)human being operating inside the Imperium’s institutions. Through him you see the Adeptus Terra, the Inquisition, hive worlds, void ships, and the everyday grimness of life in the 41st millennium — the setting explained by living in it, not by lecture.
Why it’s such a good entry point
- You learn the setting organically. Abnett introduces the Imperium through a character discovering and navigating it, so newcomers never feel lost.
- It’s a page-turner. The thriller structure — investigation, escalation, revelation — pulls you through faster than almost any other 40k novel.
- Eisenhorn is a fascinating lead. He begins as a puritan, certain of right and wrong, and the series charts his slow, chilling drift toward radicalism — using darker means for what he tells himself are good ends.
- It’s the start of a genuine classic. Xenos opens a trilogy (continued in Malleus and Hereticus), with the linked Ravenor and Bequin series following. There’s a lot of great reading downstream.
The good
- The definitive 40k-era on-ramp. If someone wants one present-day 40k book to try the setting, this is the standard recommendation.
- Tight, confident writing. Abnett is at his most accessible here — clean prose, strong pace, real momentum.
- A morally complex hero. Eisenhorn’s slide toward “the ends justify the means” is one of 40k’s best character arcs.
The not-so-good
- It’s an opener. Xenos sets up threads the later books pay off; the biggest moral consequences land across the trilogy, not in this single volume.
- Less bolter-porn than some want. This is investigation and intrigue first, set-piece battles second — a feature for most readers, a drawback for a few.
- Early-Abnett rough edges. A couple of moments feel slightly of their time compared to his later, more polished work — minor stuff.
Who should read Xenos?
- Newcomers who want present-day 40k rather than the Horus Heresy’s distant past.
- Readers who love a good thriller or detective story dropped into a gothic sci-fi nightmare.
- Anyone curious about the Inquisition — the shadowy agency that hunts heretics, mutants, and aliens.
Not sure whether to start with the past or the present? Our Horus Rising review covers the other great entry point, and the best Warhammer books guide helps you choose.
What to read after Xenos
If Xenos hooks you, the path forward is generous. The Eisenhorn trilogy continues in Malleus and Hereticus, deepening the Inquisitor’s slide toward radicalism. From there, the linked Ravenor trilogy follows his former protégé, and the Bequin series ties the whole saga together. All of it is Abnett at the top of his game, and it forms one of the most rewarding long reads in Warhammer fiction. Our Warhammer lore reading order maps the full route.
Verdict
Xenos is that rare thing: a franchise entry point that’s also just a genuinely gripping novel. It teaches you the 41st millennium by letting you live in it, and it introduces one of Warhammer’s most compelling characters at the start of a superb arc. If you want to know what present-day 40k feels like, start here.
Our rating: 9 / 10 — the best introduction to Warhammer 40,000’s current setting.
Frequently Asked Questions
Should I read Eisenhorn or Horus Rising first?
Both are excellent starting points. Choose Eisenhorn: Xenos for present-day 40,000 and the Inquisition; choose Horus Rising for the setting’s foundational history. You can’t go wrong with either.
Is Xenos the first Eisenhorn book?
Yes. Xenos is Book 1 of the Eisenhorn trilogy, followed by Malleus and Hereticus, all commonly collected in a single omnibus.
Do I need to know 40k lore before reading Xenos?
No — it’s written to be accessible to complete newcomers and introduces the setting as it goes.
Who wrote Eisenhorn: Xenos?
Dan Abnett, Black Library’s most acclaimed author, who also wrote Horus Rising and the Gaunt’s Ghosts series.
Who are the main characters in Eisenhorn: Xenos?
The lead is Inquisitor Gregor Eisenhorn of the Ordo Xenos, who narrates the book. His retinue includes the savant Uber Aemos, the pilot Midas Betancore, the Arbitrator Godwyn Fischig and the blank (untouchable) Alizebeth Bequin. Fellow Inquisitors Titus Endor and Commodus Voke also play big roles, while the hunt targets the heretic Murdin Eyclone and the sinister Pontius Glaw.
Is the Eisenhorn omnibus worth buying?
Yes. If Xenos hooks you, the omnibus is the best-value way to get the whole trilogy, Xenos, Malleus and Hereticus, in one volume, and most editions add some Eisenhorn short stories too. It’s a big book, so the Kindle or individual paperbacks are easier to read on the go.
How many Eisenhorn books are there?
The core Eisenhorn series is the trilogy Xenos, Malleus and Hereticus, plus a later fourth book, The Magos (2018), which collects Eisenhorn short stories alongside a new novel. The story then continues through the Ravenor trilogy and the Bequin books, which are where the larger saga is heading.