Disease X stands as a symbol for a subset of emerging infectious diseases rising to prominence as a significant challenge to global health security. This comprehensive review delves into the historical context, precise definition, and illustrative case studies of disease X, including notable examples, such as COVID-19, SARS, and Ebola. The discussion then transitions to an examination of the potential origins of disease X, with a particular focus on zoonotic pathways and the influence of environmental factors. The review concludes with a suite of proposed strategies aimed at the prevention and containment of disease X, emphasizing the critical role of vigilant surveillance, swift response mechanisms, and the necessity of fostering international cooperation.