What is smoking? What makes smoking addictive? Social impact?

Smoking is a major addictive phenomenon that swept through the whole world as plague since the early 6th century BC. Trade routes, expansions of kingdoms have increased the impact and brought newer methods of usage of tobacco into existence. This article discusses about What is smoking? What are the ingredients in Tobacco that make smoking addictive? and a brief touch up on the history of smoking and the social impact it has.