This is the edition I own. I don't know how I came to review another edition.
With Norton's books, what matters about editions is mostly the cover picture. The one on this edition (the 1966 edition) is puzzling. It depicts a helmeted man (?A Falconer?) with a distorted face--not scarred, I think, but perhaps affected by a stroke?
No such character occurs in this volume, and it's not clear where the (uncredited, as far as I can discern) artist got the idea from. On the back cover is another picture, of a woman (? a witch? or maybe the Lady Aldis of Karsten?) with long flowing hair.
This is the seminal work of the Witch World series. Norton commented in at least one collection that it was intended as a one-off, and just caught people's imagination to a much greater extent than other series of Norton's.
As with other books from 1966 (cf James White's The Watch Below), this book is still in the penumbra of WWII. Simon Tregarth (whose history is somewhat elided in later books) begins as a spy on the run--a man who, encountering corruption, refused to look the other way, and fell afoul of the allies of the corrupt parties.
The book begins with his introduction to Jorge Petronius, who offers Simon a chance to sit in the Siege Perilous, which activates a gate to take the sitter to a world attuned to his (? or her?) spirit.
The book is a tetrad, with continuing characters moved to new scenes, new characters introduced, etc. Each chapter also has its own title. Summaries follow:
PART I VENTURE OUT OF SULCARKEEP:
Chapter I: Siege Perilous: Set in an unnamed city (the implication is that it's in Britain). Simon Tregarth is not sure he can trust Jorge Petronius. But has he any choice?
Chapter II: Moor Hunt: Norton later realized that the witches can't just be nameless. I mean, what if you're dealing with dozens of witches? How do you indicate which one you want to ask a question of?
The vulnerable part is the formal name, anyway. So at a later time, witches are given nicknames. In this case, Simon meets, near the gate, a witch who was on a spying mission into Alizon. It's never really made clear why she thought she could be undetected, or what she was trying to achieve. Nor, for that matter, is it clear why the people of Tormarsh tried to keep aloof from the affairs of their neighbors. This chapter also introduces Koris of Gorm, whose mother was of Tormarsh herself.
Chapter III: Simon Takes Service: The men who served at the pleasure of the Witches' Council in Estcarp are mostly the offspring of Untalented Estcarpian women. But there seems to be a sort of Foreign Legion, comprising men of other ethnicities. Or else the outlanders are incorporated into the regular troops. It's not clear, because by the time Simon has a grasp of the language, circumstances have changed significantly.
Chapter IV: The Call Out of Sulcarkeep: The Sulcars, allies of Estcarp, are a sort of cross between Norton's Free Traders and of Earth Vikings. They predominantly live on their ships, but they have a landborne settlement, containing warehouses, safe harbor etc. Later volumes have maps showing the location of Sulcarkeep, relative to places like Yle and Gorm, and make it plainer why Sulcarkeep was vulnerable.
Chapter V: Demon Battle: The 'living dead' armies of the Kolder are apparently modeled after zombies. But they're not (apparently) quite as literal-minded as zombies--apparently because they're centrally controlled.
Chapter VI: Fog Doom: Thinking about it, it's a bit odd that Simon Tregarth didn't think of aerial attack right away. The whole of the Witch World is full of unaccountable technology. The Kolder have submarines. So why wouldn't they have aircraft? Come to that, the power source at Sulcarkeep is pretty advanced technology, as well.
PART II: VENTURE OF VERLAINE
I Ax Marriage: Fulk of Verlaine (in Karsten) became Lord of Verlaine by marriage (?by rape? It's implied, anyway) to the heiress of the previous Lord. Now he has greater ambitions--he plans to marry his daughter Loyse to Duke Yvian, in hopes that the riches Verlaine acquires from storm wrack (and luring ships to their doom with false beacons), combined with family ties in high places, will translate into power. Yvian hopes that marriage with legitimate Karstenian nobility will secure his own position, since he also is a former mercenary. Nobody seems to care about what Loyse wants--except a deflowered (and thus powerless) witch--and another witch, cast ashore among the other escapees from the ruin of Sulcarkeep...
II Sea Wrack: You remember the illusory ships the witch created to deceive the Kolder? The people of Verlaine never heard of them--so they're confused when the ships just vanish...
III Captive Witch: It's just getting too cumbersome to keep trying to identify the central witch in this book by awkward phrases ('the witch who...'. So (borrowing from later books), I'm going to call her the Lady Jaelithe. After Loyse's ax marriage (which, be advised, remains questionably legal, even if unconsummated), the plan is to rob Jaelithe of her powers by the same method used on the household (former) witch. But Loyse knows the secret passages in Verlaine...
IV The Inner Ways: Loyse's escape plan hits a few hitches: and gets the odd assist...
PART III VENTURE OF KARSTEN
I The Hole of Volt: Simon and Koris, along with a few other escapees, land in a small cove, and have trouble finding their way out. The 'hole of Volt' in this case, is a tomb. Koris demands a boon of Volt, and is granted it.
II Falcon's Eyrie: The Witches of Estcarp don't approve of the Falconers--for good reason. The Falconers' misogyny is always awkwardly explained, and doesn't really compute. But the gynocratic witches don't necessarily control who the Borderers make common cause with.
III A Witch in Kars: It having become clear that the dynastic ambitions in Karsten have become a target of the Kolder (as potentially ruinously as in Gorm), the Lady Jaelithe establishes herself as an undercover sorceress in Kars--with a blank shield named Briant (that pale face seem familiar?) as her leg(wo)man.
IV: Love Potion: If the Lady Aldis is not threatened by Yvian's ax marriage with Loyse, why is she in the market for a love potion?
V: Three Times Horned: The people of Karsten had apparently never questioned the concept of outlawing people by 'thrice-horning'. In later books, Karstenian people express doubt about the wholesale application of such a process by fiat, without due process. But I've heard no discussions of the process PER SE--only of this particular genocidal application. And there seems to have been little resistance to Yvian's order, except by some people in the outer provinces.
VI: False Hawk: The Estcarpians escaping from Kars encounter a robotic hawk, presumably created by the Kolder as accessories for false Falconers.
PART IV: THE VENTURE OF GORM
Chapter I: The Riving of The Border: Most of the newly-outlawed 'Old Race' from Karsten try to escape into Estcarp. So the Borderers concentrate on keeping the border open for refugees--and closed to Karstenian pursuers. This involves recruiting from the refugees, because the Estcarpian forces aren't numerous enough.
Chapter II: Tribute to Gorm: Simon Tregarth, trying to trace the Kolder moving into Karsten, runs into an ambush.
Chapter III: The Grey Fane: The Kolder don't take prisoners from the 'Old Race', because they're not pliable when subjected to the Kolder mind control techniques. Probably they shouldn't have taken Simon, either...
Chapter IV: City of Dead Men: And women, and children... Apparently, the Kolder just killed anybody they had no use for.
Chapter V: Game of Power: The Witches' Council, with some aid from outsiders, launch a psychic attack against known targets. But this presumes that injuring or destroying these targets will have any large-scale change.
Chapter VI: The Cleansing of Gorm: The forces of Estcarp clear out the Kolder headquarters at Gorm. Then they begin to consider what to do with the Kolder technology.
Chapter VII: A Venture of New Beginnings: When there was no plan to continue the series, this was intended to be the summing up. But in the next book in the series (Web of The Witch World) it's revealed that the 'New Beginnings' in the title of this chapter are in FACT new beginnings. Also, there are quite a few unresolved issues in this first volume, which leaves room open for a sequel, at the very least. So it's possible that Norton ALREADY had plans for another volume by the time she ended this one.