As the fantasy genre fastens its grip on children's writing its landscapes seem to be growing more shadowy and indistinct. The detailed, concrete worlds of Tolkien and le Guin, in which topography, social, economic, religious and political structure, language, flora and fauna slowly and painstakingly given the solidity of the pavement outside the reader's front door, have given way to a sort of generalized other country with pseudo-medieval village or tribal communities, stark ranges of mountains, enclosed valleys, decadent cities, sinister priesthoods and wars and rumours of wars.

Diana Wynne Jones' Dalemark, for instance, seems insubstantial, at the service of her stories rather than served by them. I found The Spellcoats, in which five supernaturally gifted children foil the attempt of the evil mage Kankredin to destroy the river, "the soul of the land", and thus come to power, somewhat flimsy. The central symbol of the river is...