Book excerpt: The public sector ombudsman has become one of the most important administrative justice institutions in many countries around the world. This international and interdisciplinary Research Handbook brings together leading scholars and practitioners to discuss the state-of-the-art of ombudsman research. It uses new empirical studies and competing theoretical explanations to critically examine important aspects of the ombudsman’s work. This comprehensive Handbook is of value to academics designing future ombudsman studies and practitioners and policymakers in understanding the future challenges of the ombudsman.