From the Preface: Tobacco exposure is known to be a contributing factor for several medical conditions that result in significant direct and indirect costs. The impact of tobacco and its effects on the employee-employer relationship is underappreciated and is one of the focuses of this issue of "Clinics in Environmental & Occupational Medicine". "Clinics in Environmental & Occupational Medicine" provides comprehensive, state-of-the-art reviews by experts in the field provide current, practical information on the diagnosis and treatment of conditions affecting the environment or workplace.