Secrets are one of the central themes in the book, although they are not the most prominent theme, they are quite important, as the ending of the book relies heavily on an untrue fact and untrue story, or rather a secret, which determines the fate of one of the characters. This quote (above in your question) particularly mirrors the quote " You never really know a person until you consider things from his point of view...until you climb into his skin and walk around it." Boo Radley remains a secret from the beginning of the book until the end and this quote relates to him as Scout and Jem try to figure him out, since he is so mysterious, yet another one of the secrets present in the novel.
Select the preposition that best completes each sentence:
Juan left his wallet on top of the dresser. Lorna fell asleep during the television show and missed the ending. Sheryl’s house is near the park, so we can walk from there.