Ben Okri knows words and books. He hardly ever mentions either of them in this volume, concentrating as he does on the word ''story'' instead, but he knows them inside and out. He's won the Booker for a novel, and is just as adept at essays and poetry. So this sample of his work can contain all of the above. The result is something that looks completely disposable and lightweight – like someone put an ISBN number on your local pizza parlour leaflet – but actually resonates with a power belying its size.