This volume presents a systematic chapter-by-chapter engagement with Derek Hook’s Critical Psychology (2014) as a foundation for the development of an emergent Critical Positive Psychology. While positive psychology has substantially advanced the scientific study of wellbeing, strengths, meaning, resilience, flourishing, and optimal human functioning, comparatively less attention has been devoted to the historical, political, ideological, relational, and material conditions under which flourishing itself becomes possible, legitimate, accessible, sustainable, and imaginable. Critical psychology provides an important point of departure for addressing this omission. Across successive engagements with critical psychological traditions including psychologisation, social constructionism, African psychology, dialogism, liberation psychology, discourse analysis, ideology critique, psychoanalytic approaches, decolonial thought, and critical examinations of power and subjectivity, a recurring question emerges: not simply why people flourish, but under what conditions flourishing itself remains viable. The volume therefore seeks to place positive psychology and critical psychology into productive dialogue, identifying both the limitations of depoliticised flourishing discourse and the limitations of critique when divorced from questions of hope, possibility, dignity, participation, and human becoming. Throughout the text, a series of provisional conceptual resources are introduced, including flourishing imaginaries, flourishing reductionism, situated flourishing, flourishing viability, possibility fracture, flourishing legitimacy, flourishing plurality, flourishing authorship, flourishing consciousness, psychopolitics of flourishing, capacity-to-flourish violation, flourishing affordance, and flourishing foreclosure. Collectively, these concepts contribute toward an emerging theoretical vocabulary capable of examining how flourishing becomes widened, narrowed, enabled, constrained, inherited, transmitted, recognised, or foreclosed across historical and ecological terrains of participation. Rather than treating flourishing as a purely psychological outcome located within individuals, this volume argues that flourishing must increasingly be understood as an ecological, relational, historical, political, and participatory phenomenon. The central contribution of the work is therefore a shift in analytical focus: from explaining flourishing itself toward understanding the conditions that sustain or undermine the human capacity to flourish. The volume establishes a conceptual foundation for subsequent works, including Toward a Critical Positive Psychology and Introducing a Critical Positive Psychology Ontology, and advances a central proposition that animates the broader research programme: if suffering cannot be understood apart from the conditions that produce it, then flourishing cannot be understood apart from the conditions that sustain it. Ultimately, the challenge is not simply to understand why people flourish. The challenge is to understand the conditions under which flourishing itself remains possible.