Governments, health professionals, patients, research institutions, and research subjects look to bioethicists for guidance in making important decisions about medical treatment and research. And yet, argues Jonathan Baron in Against Bioethics, applied bioethics lacks the authority of a coherent guiding theory and is based largely on intuitive judgments. Baron proposes an alternative, arguing that bioethics could have a coherent theory based on utilitarianism and decision analysis. Utilitarianism holds that the best option is the one that does the most expected good. Decision analysis provides a way of thinking about the risks and trade-offs of specific options. Like economics, utilitarian decision analysis makes predictions of expected good in complex situations, using data when possible, and focusing human judgment on the issues relevant to consequences. With such a guiding theory, bioethics would never yield decisions that clearly go against the expected good of those involved, as some do now. Baron discusses issues in bioethics that can be illuminated by such analysis, including “enhancements” to nature in the form of genetics, drugs, and mind control; reproduction; death and end-of-life issues, including advance directives, euthanasia, and organ donation; coercion and consent; conflict of interest and the reform of internal review boards; and drug research. Although Baron opposes current practice in bioethics, he argues that by combining utilitarianism and decision analysis, bioethics can achieve its aims of providing authoritative guidance in resolving thorny medical and ethical issues.