How do leaders make sense of a world defined by volatility, fragility, and constant change? This entry traces the evolution of dominant world concepts—SPOD, VUCA, and BANI—that have shaped leadership and organizational strategy across the past century. From the postwar ideals of order and control (SPOD) to frameworks that foreground disruption (VUCA) and psychological strain (BANI), each model captures a shifting relationship between leaders and the systems they navigate. Rather than presenting these acronyms as linear replacements, the entry highlights a growing recognition that no single model is sufficient in an age of compounding uncertainty. This recognition is exemplified by the emergent search for a “living model” of complexity: a dynamic, integrative leadership approach that draws from multiple frameworks and responds fluidly to changing contexts. By mapping this progression, the entry equips readers with a clearer understanding of how world concepts both reflect and shape the cognitive demands of leadership today.