The book examines philosophical and sociological approaches within critical theory and more widely from the vantage point of communicative reason. It seeks to revitalize the sociological dimension of critical theory by advancing a critical sociology of reason. It does so fully in the knowledge that reason is a contentious concept in sociology and other disciplines. Nonetheless, building on Habermas?s original insight, it argues that an extensively modified version of communicative reason is indispensable. This modified approach will draw extensively from Peirce?s pragmatist semiotics and critical cognitive sociology. Such a focus has significant implications for meta-theoretical, theoretical-empirical, and methodological approaches in critical theory, critical sociology, and related disciplines. This book will be of interest to readers in the social sciences, humanities, and philosophy who value the importance of a social theory of a reasonable society for their disciplines and for increasingly essential interdisciplinary activities. The book will also appeal to many in critical theory and beyond who are interested in the cognitive foundations of normative orders, including unjust or pathological as well as actually or potentially just foundations. The book emphasizes both validity and critique within communicative reason and critical theory and accordingly presents a distinctive perspective on critical-reconstructive research.