One critic wrote , `` In the twentieth century , To Kill a Mockingbird is probably the most widely read book dealing with race in America , and its protagonist , Atticus Finch , the most enduring ( long-lasting ) fictional image of racial heroism . '' One critic explains the novel 's impact by writing , `` In the twentieth century , To Kill a Mockingbird is probably the most widely read book dealing with race in America , and its protagonist , Atticus Finch , the most enduring fictional image of racial heroism . ''