We slip into a dream, forgetting the room we're sitting in, forgetting it's lunchtime or time to go to work. We recreate, with minor and for the most part unimportant changes, the vivid and continuous dream the writer worked out in his mind (revising and revising until he got it right) and captured in language so that other human beings, whenever they feel like it, may open his book and dream that dream again.
John Gardner
writing, writing-craft