Book excerpt: The study of ‘risk’ in social work involves complex interplay between human behaviour, emotion, evidence of fact, professional values and organisational systems. This book brings together contributions from key social work researchers and theorists from the UK, USA, New Zealand and Italy, writing with a focus on aspects of risk within social work. It examines key debates concerning risk in contemporary social work practice, including ethical dilemmas, approaches to decision-making and the challenges of ignorance and errors. Contributions range from the perennial challenges of how one uses formal knowledge when assessing risk to emerging risks arising from the counterterrorism agenda. This book will enable practitioners, policy makers and researchers to appreciate the complexities of risk in different settings and apply this understanding to their own practice. This book was originally published as a special issue of the Journal of Social Work Practice.