Simply viewing just transitions as originating in the nexus between workers’ rights and the shift from carbon and remaining fixed there, as has been advocated by some, is a dangerous practice that would remove a potentially powerful legal and regulatory tool from responses to a number of stressors to the continuation of established industries. Instead, the theoretical framework of this book demonstrates that, while paying homage to the foundational nexus from which just transitions emerged is critical to grasping it as a concept, this nexus is the beginning rather than the end. In this understanding, there are multiple facets of law, policy and economic factors which are integral and build upon each other to create a sophisticated tool for addressing current and evolving challenges. Placing an emphasis on the economic aspects of just transitions is obviously quite important, however, failing to take into account the social and socio-economic impacts and changes inherent in a durable application of just transitions risks a shallow version of the potential power of just transitions to affect long-term change. For these reasons, this chapter sets out parameters of the legal and regulatory background applicable to the development of just transitions in a largely carbon and labour nexus-oriented context. In doing so, the chapter charts the development of just transitions into an international tool that has been incorporated into hard and soft law commitments as well as a legal and regulatory tool in the European Union and throughout a number of States seeking to transition from entrenched industries in order to achieve net zero and decarbonisation commitments.