There is an astonishing discrepancy between the importance of job security regulations, understood as restrictions on hiring and firing, for employees, their prominence in explanations of un­satisfying labour market outcomes, and the amount of research on their determinants. In surveys, job security always comes out as one of the most desired job characteristics. Job security, how­ever, is not a popular topic in contemporary scholarly research. Here, job security regulations are often treated as an important impediment to job creation. In contrast to other usual suspects like unemployment benefits or collective bargaining, job security is often seen by social scientists to be of minor importance for an individual’s position in the labour market. This is due to distributional effects of job security regulations. It is argued that these regulations benefit labour market insiders, but hurt the weakest in the labour market. Consequently, flexicurity, the combination of security through the welfare state and a flexible, unregulated labour market, has become the magic formula in social policy. In contrast to the prominence of job security regulations in scholarly work on (excessively) rigid labour markets and (necessary) social policy reforms, little is known about the determinants of job security regulations. It is this gap in the scholarly literature that the present book addresses by examining the political and institutional determinants of job security regulations.