There are lots of myths about cigarettes: that "lights" offer protection, for one, or that filters actually filter.

Yet another myth is that cigarettes are just tobacco rolled in paper. Nothing could be further from the truth. The cigarette is a surprisingly complex artifact, as we now know from the treasure trove of documents released in the course of litigation. The tobacco archives online at legacy.library.ucsf.edu contain some 80 million pages of formerly secret industry documents, almost all of...