'The Moon of Gomrath' is the wild magical sequel to 'The Weirdstone of Brisingamen', set in Alderley Edge in Cheshire of the present day but harking back to the days of Middlearth. Both these stories have a very Tolkienish way about them, it is an interesting exercise to compare and contrast the characters as they are introduced. It is a pity that Garner's books, faring less well than 'The Hobbit', dropped off the literary radar in the 1980's, but with the benefit of Potter power they are now back in style with new artwork on the cover.
Garner's special art is to take a basic swords-and-sorcery story and elevate it into a poetry-and-powers myth with gritty heroes and terrifying villains who hard to defeat and not always easy to spot. This story of Colin and Susan's second adventure is aimed at a slightly older audience than the Weirdstone, has Susan in the lead role, and has more depth and menace along with some sly humour. The Morrigan is back, not yet at the height of her powers, but ready for revenge. The elves are suffering and dying from the pollution caused by Man: they must retreat to cleaner, remoter places. The battles in magic and swordplay are more deadly and more personal and more realistic. The havoc and hard pace of war are felt in the prose, which is breathless and a little wild itself. The wizard Cadellin takes more of a back seat in this adventure but he does explain (in chapter four) why the coming of the 'Age of Reason' and industrialism was more of a coming of the age of Materialism and a retreat from Reason. Hence the great rift between our Man's world of material values, and the worlds of magic and the life of the spiritual values.
Now as every parent knows, children's books have the power of forming the child's mind. (True even in the age of film and video, as books are both more personal and make mind-expanding demands on the imagination. Films just fill up whatever space is in your head, they do not create it. Books are not just good for you, they are more fun.) So with magical adventures being very much back in style now is a good time to get the various authors into some sort of order. So, without going back to the ancient Greeks, where does Alan Garner fit in? We can easily go back a century or so: F. Anstey (Vice Versa), George MacDonald (Princess and Curdie stories), and E. Nesbit (House of Arden, etc), Tolkien (Hobbit, Farmer Giles of Ham), C.S. Lewis (Narnia, the land of youth), Ursula K. LeGuin (Earthsea), and Alan Garner. And, as Rowling's ghost Peeves puts it, 'Wee Potty Potter', brings us up to date.
So there are two main routes to magic. Anstey, MacDonald, Nesbit, Garner, and Rowling write a story that exercises magic in this world, and the two things collide with exciting degrees of chaos and depth. The results are serious or hilarious, or both. Garner manages to interface the two worlds with superior art. But a higher priced ticket will take you to a whole new world. Tolkien, Lewis, and LeGuin create whole worlds of their own and people it with new peoples - a fully magical world. The magic is integrated, truly part of the fabric of that world, not just added to make it fizz. One you are in, you belong there for a while. You return and your own world is now a little more magical. The whole range of literary forms is now possible, even super-possible as we no longer rely on supposed 'realism' to make the effects. They go beyond just making a magical talisman or two (some brilliantly done, others less so), and seeing 'what happens'. They make new countries and skies, new kingdoms and peoples, new languages and rules. Ultimately they are the suns and the others are the moons.