Book excerpt: The scientific field of leadership and followership is fast evolving and has seen several interesting developments over recent years. The early heroic views of leadership are slowly turning into more nuanced perspectives, including the understanding that leadership and followership are mutually dependent on each other. Likewise, there is a growing awareness that the focus on the positive side of leadership and followership can be fruitfully complemented by a focus on the darker sides of these constructs. According to the latest research plenty of “grey areas” exist, where further insights into leadership and followership are needed. We seek to emphasize the different shades of dark leadership by taking leaders, followers, and their interaction in specific contexts into account. Accordingly, many of the findings presented in this Research Topic align with a deviation away from the idea of the omnipotent leader. Not only leaders’ dark traits such as narcissism and psychopathy, but also followers’ Machiavellianism emerged as hindering factors for positive organizational functioning. Other results presented in this Research Topic will be fruitful to explain what drives leaders towards dark-side behaviors, the consequences of dark-side leader behaviors (e.g., different types of destructive leadership), and how followers respond to them (e.g., follower attributions of perceived abusive supervision). Contributions to this Research Topic are also pushing the boundaries of current theorizing, shedding further light on the “shades of grey," when it comes to the possibly unintended negative consequences of leadership and followership. In sum, the dark sides of leadership and followership are a natural part of an organizational reality that many employees face day in and day out. The aim of this Research Topic is to encourage an integrative view of leadership and followership and their dark sides, for a better understanding of complex organizational systems and implications for better practice.