Atticus brings Scout a book home in his briefcase in part 1 of To Kill a Mockingbird. When he arrives home from work, Jem takes his briefcase and Scout asks her father if he has brought a book for her:
Jem, forgetting his dignity, ran with me to meet him. Jem seized his briefcase and bag, I jumped into his arms, felt his vague dry kiss and said, "'d you bring me a book?'" (Chapter 13)
Scout enjoys reading with her father. Together, they read a variety of texts. They read informational books, law, the Bible, and newspapers. When Miss Caroline tells Scout that she can no longer read with her father, she realizes how special their time together is.
On two separate occasions later in the novel, it is revealed that Atticus carries papers in his briefcase. These papers have to do with the legal matters he is working on, such as the trial of Tom Robinson. The following is a quote from the one of the courtroom scenes in Tom's trial:
[Atticus] had evidently pulled some papers from his briefcase that rested beside his chair, because they were on his table (Chapter 20).