Welcome to this special issue of the Journal of Social Work Practice on risk in social work. Risk is often defined in terms of the probability of harm occurring (Gigerenzer 2014); although in social work practice, the concept is far more multi-faceted. The profession is concerned with the seriousness of (i.e. negative value placed on) the particular harm as well as its likelihood. When we consider ‘risky situations’ in terms of making decisions, we are often considering both potential gains (with both their value and their likelihood) as well as the possible harms in some way or other (Taylor 2017a). Consideration of future situations raises the complex domain of deciding about preventive actions to reduce the possibility or seriousness of harm. And then there are the emotions such as wariness of lurking conflict (Taylor 2006), anxiety, fear and courage – familiar subject matter to readers of this journal – which may be an intrinsic part of such ‘risk work’ within professional practice. To give added complexity, we must consider also the organisational system aspects, such as the assessment and management of risk, which interweaves with the professional tasks (Taylor et al. 2015).