How did an addictive, poisonous, disease-causing substance become so ingrained in our culture, and ubiquitous on our store shelves despite science and better judgement? To get answers, writer Joshua Knelman tells the story of a young lawyer whose job it is to market cigarettes around the world, even as growing health concerns, government regulations and anti-smoking campaigns would seem to signal the demise of the product he's hawking. In his new book "Firebrand: A Tobacco Lawyer's Journey" Knelman takes us inside the global tobacco industry to explore why and how the tobacco trade thrives as much, if not more, than it ever has.