The author has a very good site that addresses the book's complex themes and it includes reproducible worksheets. E. answered all the thoughtful study guide questions, which works well as an approach to assess reading comprehension.
"Judging from his tracks, Boo was about six and a half feet tall, dined on raw squirrels and any cats he could catch. There was a long, jagged scar that ran across his face. His eyes popped and he drooled most of the time." Jem describing Boo Radley in To Kill a Mockingbird "Facts are stubborn things." Tobias Smollett