The Deep Transitions framework expands sustainability transitions research by analysing the long-term co-evolution of multiple socio-technical systems. It argues that current system configurations drive both environmental crises and social inequalities. Unlike traditional transition studies, which focus on single systems, Deep Transitions links historical trajectories - such as the Industrial Revolution - to the First Deep Transition, marked by fossil-fuel reliance, mass production, and unchecked resource use. The framework integrates sustainability transitions theory with longwave economic cycles, emphasizing shared meta-rules in shaping industrial modernity. Empirical applications include historical analyses of mass production, international governance, and wars as landscape shocks. The envisioned Second Deep Transition aims to reconfigure socio-technical systems towards planetary sustainability and social equity. Future research should refine the framework through empirical testing, engagement with socio-ecological systems, and governance innovations. Deep Transitions challenges conventional approaches by highlighting systemic inertia, global inequalities, and the need for a just transition.