This Background Paper for the International Expert Working Group (IEWG) for a New Development Paradigm outlines the concept of well-being, flourishing, and happiness for all, which forms the objective of a new development paradigm. It seeks to synthesise for busy readers how the IEWG might explain and defend well-being and happiness, and also what value-added this work has in policy terms. The paper draws upon philosophical traditions to propose how the GNH concept of having nine domains of well-being can be shared in an international context. Each of the nine domains are already the subject of numerous policy proposals, and where these are well-developed, this document suggests that the commission affirm others’ work. We then look beyond these and draw attention to more radical policies and overlooked aspects of each domain, that are visionary yet efficient. Taken together, these policies illustrate the implications of focusing squarely on human flourishing as our fundamental objective. In each section, we convey concrete possibilities, by mentioning feasible and high impact policies which are cost-effective or cost-saving. Such policies are the kinds needed to reframe and reorient our institutions towards well-being and happiness, and their consideration will spark other examples or possibilities in readers’ minds. The third and final section draws attention to the behaviour changes needed to undergird this new paradigm, and draws a realistic hope for the future.