This textbook examines the ways in which arguments may be used and abused in medicine and health. The central claim is that a group of arguments known as the informal fallacies - including slippery slope arguments, fear appeal, and the argument from ignorance - undertake considerable work in medical and health contexts, and that they can in fact be rationally warranted ways of understanding complex topics, contrary to the views of many earlier philosophers and logicians. Modern medicine and healthcare require lay people to engage with increasingly complex decisions in areas such as immunization, lifestyle and dietary choices, and health screening. Many of the so-called fallacies of reasoning can also be viewed as cognitive heuristics or short-cuts which help individuals make decisions in these contexts. Using features such as learning objectives, case studies and end-of-unit questions, this textbook examines topical issues and debates in all areas of medicine and health, including antibiotic use and resistance, genetic engineering, euthanasia, addiction to prescription opioids, and the legalization of cannabis. It will be useful to students of critical thinking, reasoning, logic, argumentation, rhetoric, communication, health humanities, philosophy and linguistics. 37 Illustrations, color; XVI, 418 p. 37 illus. in color.