Civilisation and Human Systems: The Structural Logic of Human Systems at Civilisational Scale challenges one of the most established assumptions in the study of human societies: that institutions can be understood in isolation. Instead, it argues that, beyond a certain threshold of complexity, the fundamental unit of analysis ceases to be the institution and becomes the civilisational system of systems. In an environment defined by global interdependence, technological acceleration, economic transformation, geopolitical uncertainty and growing social complexity, civilisations can no longer be understood solely as historical phenomena. They must be approached as complex, multi-layered and adaptive systems capable of evolving over time without losing coherence, legitimacy or strategic direction. Through the concept of Civilisational Systems Architecture (CSA), Fernando Privat proposes an integrated framework for understanding the structural architecture of human systems at civilisational scale. The work brings together systems thinking, institutional theory, governance, systems theory and systems design to examine the interaction between human capital, institutions, strategic decisions, culture, meaning and adaptive capacity. The book develops four central frameworks: Civilisational Systems Architecture (CSA), which defines the fundamental layers of the civilisational system; the Civilisational Dynamics Model (CDM), which examines expansion, stability, crisis and transformation; the Systemic Coherence Model (SCM), which analyses alignment across the system’s different layers; and the Civilisational Intelligence Index (CII), which addresses adaptive capacity, anticipation and resilience. The work demonstrates that civilisational stability depends not merely on size, power or resources, but on the capacity to maintain coherence while evolving under increasing complexity. It further examines systemic adaptation, legitimacy, resilience, strategic foresight, institutional evolution and intergenerational design as essential capabilities for the long-term sustainability of human systems. Written for business and institutional leaders, policymakers, investors, researchers, strategists and governance specialists, this book offers a new scale of analysis for understanding not only how civilisations function, but how they may be understood, evaluated and, at certain levels, deliberately designed to meet the challenges of the long term.