Universalism is collapsing in real time. As Western hegemony wanes, the promise of universal values is unmasked as a parochial inheritance; and as AI systems multiply, universal truths transform into computed artefacts emerging from a particular code and training. In Concrete Universality, Lorenzo Marsili argues that the choice is not between a bankrupt universalism and an 'anything goes' relativism. He proposes a third path: universality as a practice of worldmaking. Drawing on Chinese philosophy, European thought and the contemporary metaphysics embedded in artificial intelligence and quantum mechanics, Marsili develops the concept of ontopoiesis: the idea that reality is continuously produced through relations and forms of mediation. This approach gives rise to a new political method: a 'concrete universality' emerges from situated encounters yet gains planetary resonance, from AI regulation to climate policy. Here, universality is not a static ideal, but an unfinished voyage whose horizons move as humanity moves. This book is an erudite and impassioned manifesto for a planetary philosophy and a way of weaving together a fragmenting planet, one universal at a time.