One of the things a writer must remember is that a book is a collaboration between the writer and the reader. When a reader constructs the images in their mind from my words they are using the powers of their imagination to make the story come to life. (Sebastian Faulk's new programme on the BBC which celebrates famous literary personalities demonstrates the power of the imagination of the reader for whom these fictional people - Heathcliffe or Lady Chatterley- have become real.)
So the worst reader as far as a writer is concerned has to be the reader with no imagination, who fails to be able to imagine the story world from the clues I have left them on the page.
Each reader's construct of the book they are reading is unique.
"For all the voices and masks of my performance, there is an intimacy with the reader. We are in this game together. Reading, real reading, is a strenuous and pleasurable contact sport. Fun, but it's not television. In "Art Objects" Jeannette Winterson calls reading sexy. I'll go along with that smart idea. Reading, I might say to my students, is not like dating; it's a matter of full engagement." Maureen Howard
So you might think then that a good reader might have a store of images or large amount of life experience, have met many different sorts of people so that they will be able to recognise something of my descriptions and identify with them. That is helpful, yes, but I think good readers are more - they are practised imagineers.
Imagination comes from practice - the more you read, the more adept you become at slipping into the fictional world you are reading. The more fictional characters you meet the easier it becomes to recognise and identify with certain types. Imagineers also imagine other things and are creative in other ways, however small, because reading is a creative act.
Of course as a writer it is our task to supply the reader with enough clues to be able to imagine that our characters live independent lives apart from the book. Some clues might seem as though they are useful but actually inhibit the imagination. Personally I do not like too much description of physical appearance. If for example I tell you that "Joan is blonde, 37 years old, dresses in pastel pink skirt and white shoes" then you will get a picture in your mind of Joan. However this may not be the sort of imaginative hook that will allow a reader to begin to make up an imaginary life for Joan. If on the other hand I tell you little about her appearance but say, "In our office, Joan was the person people forgot to ask when ordering the coffee," then maybe you might start to get to know Joan on the inside a little more and want to empathise with her and start to grow her a life.
Too much obvious research can kill a novel, and the flow of a story. We want to get the reader to contribute their half of the story and not do all the imaginative work for them. If I leave nothing to the reader the book will never be able to take flight in their heads.
There is a famous story about John Buchan, who wrote dozens of successful adventure novels. At one point in his career he was going to write a novel about the Canadian Arctic. This was way before he arrived in Canada to serve as governor general, and he knew nothing at all about Canada. Fortunately for him, his son had just returned from spending a year there.
"Tell me 10 facts about the Arctic," John Buchan demanded. The son began to list them, but his father interrupted after just three facts had been delivered: "That's enough. That's plenty. I can manage with that."
The rest he went ahead and invented.
Or rather the reader went ahead and invented.