This volume brings together the abstracts of the IX Aretai International Conference on Human Flourishing, Psychological Well-Being, and Virtue, held at the European University of Rome from 15 to 17 September 2025, organized by Aretai – Center on Virtue, in collaboration with the PROBEN Project (4 Challenges 4 Well-Being), a major national research initiative funded by the Italian Ministry of University and Research. The contributions address the need to articulate a more comprehensive account of well-being from a variety of disciplinary and methodological perspectives. They examine the conceptual relationships between flourishing, well-being, and happiness; the role of virtue in shaping both individual lives and social practices; and the conditions under which human capacities can be developed and sustained. Particular attention is devoted to processes of virtue formation and to their implications for fields such as education, healthcare, and public policy. Several contributions also engage with methodological questions, exploring how qualitative and quantitative approaches may be productively combined in the study of human flourishing and well-being. The volume offers an open inquiry, grounded in a careful balance between theoretical reflection and practical application, and aims to foster further research, dialogue, and collaboration towards a deeper understanding of how individuals and communities may genuinely flourish amid the multiple challenges of our time.