Global problems require global solutions. However, the United Nations, as presently constituted, is incapable of addressing many global problems effectively. One nation-one vote decision-making in most UN agencies fails to reflect the distribution of power in the world at large, while the allocation of power in the Security Council is both unfair and anachronistic. Hence, nations are reluctant to endow the UN with the authority and the resources it needs. This book is rooted in the proposition that the design of decision-making systems greatly affects their legitimacy and effectiveness. It proposes numerous systemic improvements, largely through weighted voting formulae that balance the needs of shareholders and stakeholders in diverse UN agencies. It indicates ways by which the interests of regions can supplement those of nations and by which the voices of non-governmental organisations and ordinary citizens can also be heard. In numerous contexts, it promotes meritocracy and gender equity.