The agri-food sector is undergoing profound transformation in response to escalating global challenges related to sustainability, resilience, and digital integration. This chapter provides a comprehensive introduction to Industry 4.0 and its growing significance in driving the sustainable transformation of agri-food systems. It begins by tracing the historical progression of industrial revolutions, highlighting how each phase has reshaped food production, processing, and distribution. Building on this context, the chapter defines Industry 4.0 as the convergence of digital, physical, and biological technologies, and identifies its core enabling technologies. It also introduces a set of emerging concepts, such as Quality 4.0, Traceability 4.0, Processing 4.0, Packaging 4.0, and Supply Chain 4.0 that exemplify how innovative technologies are redefining the way food systems ensure high quality, safety, efficiency, accountability, and resilience. The chapter then presents Food Sustainability 4.0 as a forward-looking framework that leverages these technologies to support environmental goals, social objectives, and economic sustainability. By addressing persistent challenges such as infrastructure limitations, financial constraints, and the digital divide, the chapter emphasizes the need for coordinated efforts among food stakeholders to ensure inclusive, responsible, and equitable adoption. Overall, it offers both theoretical foundations and practical insights into the role of Industry 4.0 in advancing sustainable, resilient, and technology-driven food systems.