This introductory chapter sets the foundation for Large Floating Solutions: Design, Construction, Legality of Offshore Structures and Buoyant Urbanism by presenting buoyant urbanism as a timely and necessary response to the escalating global water crisis driven by climate change. As urban centres increasingly face recurring floods and sea-level rises, floating urban developments offer a transformative approach to climate adaptation, resilience and sustainable urbanisation. The chapter draws on historical and contemporary precedents, showing how communities have long adapted to life on water through floating and amphibious settlements. It then examines the technological, environmental and legal frameworks that underpin the viability of modern floating cities. These include advances in Very Large Floating Structures (VLFS), modular construction systems and the integration of marine ecosystems, alongside emerging legal and policy mechanisms to regulate these developments. Positioned within the framework of the United Nations Sustainable Development Goals, buoyant urbanism is framed not only as a strategy for flood resilience but as a new frontier for reimagining urban futures. As an entry point to the book’s interdisciplinary exploration, the chapter outlines the structure and themes of the volume and calls for a paradigm shift in urban planning that embraces the adaptive and generative potential of living on water.