The aim of this book is to evaluate the functioning of the Security Council during its first 75 years, from an institutional legal perspective. It analyzes three issues that were not only hotly debated when the United Nations was founded, but have also been highly relevant for the Council’s functioning in practice and are likely to remain so in the future: the right of veto for the permanent members, the rule of law, and the size of the Council (the need for enlargement).