One of the things I value most about reading is the ability of a well written book to put you into a world outside of your realm of experience. With much of my fiction reading those worlds are outside everyone's realm of experience, I don't know anyone whose lived through "the Princess Bride" or Pullmans "His dark materials" books. They are fantasy and are given meaning through the skill of the writer in creating "real" characters and situations within the fantasy that have greater resonance with the world outside. Then there's Walter Mosely's "Little Scarlet" set in the aftermath of the Watts riots in LA at the tale end of the 60's. I have no idea what it would be like to ride a segregated bus, to be threatened by police or attacked by strangers because of the colour of my skin but reading Mosely's Easy Rawlins books I can get a small insight. Mosely captures the sense of fear and anger that comes from living in such a world so well that it becomes tangible and it's made all the more real when you read of gangs attacking a mna simply for being Polish or black teenagers being shot in London.
We live in a country where racism is still institutionalised to too great an extent and a chance to walk in another man's shoes gives you a chance to see your part in this evil and see what it's like on the other side.