We form many of our opinions from our favorite books. The author whom we prefer is our most potent teacher； we look at the world through his eyes. If we habitually read books that are elevating in tone， pure in style， sound in reasoning， and keen in insight， our minds develop the same characteristics. If， on the contrary， we read weak or vicious books， our minds contract the faults and vices of the books. We cannot escape the influence of what we read any more than we can escape the influence of the air that we breathe.