Another excerpt from Philip Pullman's Daemon Voices, this time from the essay 'Reading in the Borderland':
"The borderland, the land along the frontier, is the space that opens up between the private mind of the reader and the book they're reading. It'll be different for every individual, because while parts of the borderland belong to the book, other parts belong only to that particular reader - to us: our own memories, the associations we have with this or that particular word or landscape, the aspects that resonate with our own individual temperament; so whereas many readers might be reading the same book, no two of them will read it in exactly the same way.
We are each alone when we enter the borderland and go on to explore what lies in it and beyond it, in the book we're engaged with. True, we can come back and talk about it and if we talk well and truthfully and interestingly enough we might entice other readers into it, and they too will explore it - but they too will be alone there until they in turn come back and tell us what they found there. And it may be that they will find treasures beyond compare that we've overlooked, or that the things that strike us as marvels will seem to them commonplace and not worth discussing."