Few things in life make me happier than a well-crafted (American) football playbook. It lays out a coach's foundational principles and underlying philosophy. It defines how they intend to do the big things and, through the plays themselves, the small things too. Combing through one as a writer or fan, you are guaranteed to learn something about the sport you already think you know quite a bit about. (It's basically the entire reason I have a Scribd subscription -- sometimes, random playbooks show up there.)
Thanks to Andrea Pirlo, I now know that it works the same way for soccer.