When it comes to the field of organization and management theory, a philosophical perspective enables us to conduct organizational research imbued with the attitude of ‘wonder’; it helps researchers question dominant images of thought underlying mainstream thinking, and provides fresh distinctions that enable the development of new theory. In bringing together a collection of key essays by Haridimos Tsoukas, this volume explores fundamental concepts, such asorganizational routine, that have gained currency in the field, as well as revisiting traditional concepts such as change, strategy, and organization. It discusses organizational knowledge, judgment, and reflection-in-action, and, at the meta-theoretical level, suggests complex forms of theorizing that dojustice to the complexity of organizations. The conceptual attention throughout is on process and practice, underlain by performative phenomenology and an emphasis on agents’ lived experience. This provides us with the language to appreciate the dynamic character of organizational behaviour, the embeddedness of action, and the complexity of organizational life. The theoretical claims presented in this volume have important implications for practice, insofar as they help retrain our attention; from seeing structures and individuals, wecan now appreciate processes, experiences, and practices. A phenomenological attitude makes organization theory more open, more creative, and more reflexive, and this book will be essential reading for researchers and students in the field of organization studies.