The emergence of life hinges on a mutual evolution between compartments and their encapsulated content, addressing the paradox where each one seems to require the other to function. This chapter frames compartmentalization as a gradual progression rather than a sudden biological invention. We first review how primitive compartmentalization, including limited diffusion in geological pores, transient coacervates, and permeable vesicles, supports ground evolutionary properties such as reproduction, heredity, and the mitigation of the so-called “Error catastrophe.” We examine the experimental state-of-the-art, highlighting how mineral surfaces scaffold chemical networks and how phase-separated coacervates serve as dynamic, membraneless microenvironments for ribozyme activity. Then, we describe the transition from simple fatty acid vesicles to robust phospholipid membranes, based on “missing link” lipids that bridge this evolutionary gap. Finally, we propose a complete nine-stage evolutionary arc, depicting the putative shift from environment-dependent chemistry to autonomous protocells capable of regulated cell cycles.