If satisfies the other-world dreams of youth, is emphatically for adults, and not only because the sex and violence are explicit. Martin's leading characters mostly act on Machiavellian principles. gets its title from a phrase the characters sometimes apply to their amoral power struggles. "When you play the game of thrones, you win or you die. There is no middle ground," the vicious Queen Cersei tells Eddard Stark, the nearest thing we have to a hero.

Compared to , is morally complex and undecidable. "No character is without moral ambiguity," observes critic and Martin admirer Amanda Craig. There are no Aragorns or Gandalfs, with their uncompromised nobility. Even the best of Martin's characters can be ruthless or wrong. Tolkien's Mordor is the home of all evil; Martin is more interested in the kinds of viciousness, ambition and vengefulness we recognise from human history.

The escape into a world we are invited to dream up with the novelist's assistance is inherent to fantasy. The main assistance is provided by the maps that preface every book in the series. This is how you know you are beginning a work of fantasy fiction: you open the book to find an apparently hand-drawn map of lands unknown to any previous atlas-maker.

These novelistic cartographers are all following Tolkien's lead. Tolkien provided the beautiful hand-inked maps that folded out of the original three hardback volumes of

Fantasy is also distinguished by the presence of magic. Yet, since the 1960s, serious literary fiction has supped full from the magic cup. In Gabriel García Márquez, it is animistic brilliance; in Salman Rushdie's , a way of making an individual's story into a historical tale. Perhaps the difference is that in fantasy fiction, magic is such serious stuff, and subject to complex rules and rationales. Children schooled on Harry Potter books, with their minute explanations of patronuses and horcruxes, are well prepared for the modus operandi of most adult fantasy fiction.

In Martin's novels, magic is much more limited. After a brief, unsettling prologue, which introduces the threat of the undead Others, hanging over all that follows, he holds the supernatural back as long as he can. We are almost 700 pages in before some dubious necromancy seems to bring the mortally wounded husband of one of the protagonists back from the brink of death - and even then we can't quite be sure that a spell has been cast. Magic is a possibility rather than a fact, necessary simply to mark the difference between the world of these novels and our world.

Gaiman specialises in stories that do not so much take us to other worlds as admit the deities and demons of different mythologies to this one. The AU is in our midst. takes an inhabitant of modern-day London into "London Below", an alternative world of terrifying trials and magic.

Gaiman is a student of mythography; a reader of his fiction is offered all the pleasures of tracking down his sources. His novels have an encyclopaedic aspect. They also provide adult wit among their frightening tales. It is no surprise he has collaborated with fantasy's licensed jester, Pratchett, whose career began by recognising and deflating the genre's habitual solemnity. Pratchett's first Discworld book, , was, in effect, an affectionate, Pythonesque send-up of Tolkien and his progeny. The wizard is a bungler, the gods are silly and the dialogue cheerfully cynical. Yet many of Pratchett's readers must also be readers of fantasy fiction, able to relish the irreverent parody as well as the real thing.

In his fiction, Pratchett is a humorous commentator on the allure of fantasy conventions. A more serious commentator is Ishiguro, whose has led critics to wonder aloud whether elements of the fantasy genre might not be more interesting than they supposed.

As its central characters, an elderly couple called Axl and Beatrice, travel on foot to find their lost son, they hear about ogres and fiends; they meet an aged and dilapidated Sir Gawain, who talks of his quest to slay a dragon.

Ishiguro has spoken of the influence on the novel of the wonderful 14th-century narrative poem , whose less-than-heroic hero undertakes a lonely journey across a wintry landscape to encounter the terrifying Green Knight. It is near the novel's conclusion that the main characters come together to encounter that favourite inhabitant of fantasy fiction: a dragon.

On the very last page of , three dragons are born. Not all fantasy novels have dragons, but many do. C.S. Lewis and Tolkien had dragons and Ishiguro knows a dragon is a test of how far he is willing to go down the fantasy road. His superstitious characters talk of the dragon so fearfully that it is a surprise for the reader when we actually find her, near the end of the novel, a matter of reptilean fact.

Through the novel we catch hints of terrible events in the not-distant past. Ishiguro is using some of the conventions of fantasy fiction to produce a fable about violence and the capacity of societies to forget the violence of their pasts.

Fantasy sometimes deals evasively with violence. Tolkien specialises in battles that seem almost decorous. Martin's novels, in contrast, dwell on the details of violence, as if insisting on seeing what some of his fantasy forebears managed to ignore. He particularly likes to insist on the violence done by those characters with whom we might want to sympathise.

In Martin's world, you do best to assume people act from the lowest of motives. It is a tough old world and the weak are more, not less vulnerable. In a frequent narrative pattern, a child or a woman will be saved from violence by one of the leading characters - only to be casually slaughtered a few pages later. Near the end of , Wistan, the Saxon warrior, explains the novel's title. "The giant, once well buried, now stirs …" Unacted violence brims. Fantasy fiction has an apocalyptic inclination. foresees, but then improbably staves off, the triumph of darkness. Martin's still endless epic sees bad things in the future ("Winter is coming," as everyone keeps saying), but also finds violence entirely ordinary.

Still, Martin also knows all about creating curiosity and suspense. He keeps shifting the reader's focus in order to leave him or her, at the end of each chapter, with a puzzle posed, an apprehension activated, or a surprise sprung. He has a great ability to manipulate narrative expectation. Ingeniously, he satisfies a hunger that all novel readers know, whether they are willing to enter the fantasy room or not.