Plague, deception, and spies in a steampunk setting. Cara Lenoir knows all about secrets. Her existence is one. To keep her sister, the queen, safe from their monstrous father, Cara hides as Carl Fletcher, physician’s apprentice. It’s either that or die. But when Nathan Cutter shows up to be her mentor, danger lurks closer. What hope does a physician have against a ruthless killer? A deadly plague reaps in the slums. A network of spies is closing in on her. Under the Mantle, Cara has nowhere left to hide.

This report considers the biological and behavioral mechanisms that may underlie the pathogenicity of tobacco smoke. Many Surgeon General's reports have considered research findings on mechanisms in assessing the biological plausibility of associations observed in epidemiologic studies. Mechanisms of disease are important because they may provide plausibility, which is one of the guideline criteria for assessing evidence on causation. This report specifically reviews the evidence on the potential mechanisms by which smoking causes diseases and considers whether a mechanism is likely to be operative in the production of human disease by tobacco smoke. This evidence is relevant to understanding how smoking causes disease, to identifying those who may be particularly susceptible, and to assessing the potential risks of tobacco products.