A 40-hour working week is the norm in Europe, yet some organizations require 60 or more working hours and in investment banks an alarming 120-hour weeks are known to be worked. What is more, these organizations often require workers to be permanently on call and demonstrate high production rates. Consequences of such practices include frazzled employees, with their families’ and their own health under pressure. This article introduces our special issue of the German Journal of Human Resource Management. It tackles the many reasons behind excessive work hours and failed attempts to change working time arrangements in organizations. It first identifies three core ideas in previous research, namely the dispersed nature of regimes of excessive working hours, their high levels of persistence and their constitution at multiple levels of analysis. It then summarizes the contributions in this special issue. Finally, it proposes avenues for future research, such as focusing on the genesis and the historicity of organizational working time regimes, studying the interrelation of factors across multiple levels of analysis, and probing new theories to explain the extreme persistence of excessive working hours. The overarching aim of our special issue in this core area of human resource management is to contribute to an understanding of organizational working time regimes and the tenacity of excessive working hours in an effort to deepen our knowledge of how to change them.