What Really Makes You Ill? Why Everything You Thought You Knew About Disease Is Wrong by Dawn Lester and David Parker argues that the modern medical establishment’s focus on germs as the primary cause of illness is incorrect. The authors argue that illnesses are caused by environmental toxins, nutritional deficiencies, and lifestyle factors, suggesting that "germs" are symptoms rather than causes. The book is a 700+ page investigation into what the authors describe as significant inaccuracies in modern medicine, encouraging readers to re-evaluate their understanding of health and illness.