This article presents an overview of contemporary research into patient safety. The article suggests that patient safety research to date has tended to privilege the formal and structural dimensions of safety at the expense of the social and affective dimensions of safety. The article previews the research articles brought together in this special issue of Social Science & Medicine, paying particular attention to the impact of these studies on the field of patient safety research generally. The present article summarises this impact in the form of the following three patient safety research principles. First, to account for whether and how safe and improvement-oriented practice is achieved, research must engage with both the predictability and the complexity of the sites and processes it seeks to describe, explain and/or impact on. Second, engaging with complexity implicates researchers in experiencing it, and this implicates the research process and its methodology in a process of sense-making of the practical and affective consequences for and with practitioners inhabiting and enacting that complexity. Third, besides numerically-based descriptions, abstracted explanations and procedural prescriptions, patient safety research evidence must encompass experiential data, collaboratively-produced accounts and/or experience-based designs.