This investigation addresses research on healthy volunteers, children, vulnerable subjects, and includes placebo controlled clinical trials. It represents a major contribution towards clarifying the most central, but also the most controversial and complex issue in biomedical research law and bioethics. The EU Clinical Trial Directive, the Council of Europe’s Oviedo Convention (and its Additional Prool), and national regulation in member states are covered. It is a relevant work for lawyers and ethicists, and the practical approach makes a valuable tool for researchers and members of research ethics committees supervising biomedical research.