Lifestyle Medicine: Lifestyle, the Environment and Preventive Medicine in Health and Disease, Third Edition, is an adjunct approach to health practice that seeks to deal with the more complex modern determinants of chronic diseases—primarily lifestyle and the environments driving such lifestyles—in contrast to the microbial ‘causes’ of infectious disease. Our lifestyle choices have a profound effect on our health. As we live longer, one thing is clear: many of us will spend time living with injury and chronic illness due to our own choices. Changes in health patterns typically follow shifts in living conditions. Disease patterns have changed worldwide, from infectious to chronic diseases such as obesity, diabetes, and heart disease. This change has been so emphatic—nearly 70% of all presentations to a doctor in modern western societies are now chronic disease related—that medical services are being forced to change to accommodate this. New chapters in this third edition explain the link between energy intake and expenditure; consider how modern technology are determinants of chronic disease; show how environmental influences, such as endocrine disruptors, influence our health; and summarize recent research on early childhood experiences and chronic disease.