Off the top of my head, every book I can think of that provides deep insight into the human condition does require putting in some work. Let's take as an example "Night" by Elie Wiesel, a book that is written so simply it is typically assigned in middle school (that's when I read it). Well, it was assigned in school for a reason -- there's a lot of work to put in to learn more about the history of the Holocaust, concentration camps, and specifically the death marches, as well as the actual full biography of the author (the novel is an autobiography but it only covers one early part of his life).