The best part about the book is the way in which it conveys important messages without being preachy. The ability of Atticus, the protagonist to stand by what he believes, even in the face of adversity is something that forces the reader to think. The innocence of the kids and how Atticus deals with it, along with laying certain important ground rules that would lay the foundation of their personalities is a lesson which all of us could learn from. The entire emphasis of the book according to me is to get the basics and the fundamentals right. Rest things will fall in place.
Hats off to Harper Lee for writing this masterpiece.