The chapter discusses the evolution of manufacturing systems from job shops to high-volume, low-variety dedicated lines, and the introduction of flexible manufacturing systems (FMSs) in the 1980s to address mass customization and responsiveness to changes. FMSs provide built-in flexibility for anticipated variations but have high initial costs and can underutilize their flexibility attributes. In the 1990s, key drivers like optimality, agility, waste reduction, and lean manufacturing emerged. The concept of reconfigurable manufacturing (RMS) has since emerged, aiming to achieve changeable functionality and scalable capacity by allowing quick adjustments to machine components, cells, or material handling units. RMS is seen as potentially more cost-effective in the long run compared to FMSs, though it requires significant changes in hardware and software. The chapter reviews recent research on manufacturing system flexibility, its measurement, and impact, and introduces the concept of a manufacturing system life cycle. It also compares the characteristics and prerequisites of FMSs and RMS, highlighting the importance of human-machine integration and the role of people in various manufacturing paradigms. Finally, it discusses the industrial and research challenges associated with these paradigms.The chapter discusses the evolution of manufacturing systems from job shops to high-volume, low-variety dedicated lines, and the introduction of flexible manufacturing systems (FMSs) in the 1980s to address mass customization and responsiveness to changes. FMSs provide built-in flexibility for anticipated variations but have high initial costs and can underutilize their flexibility attributes. In the 1990s, key drivers like optimality, agility, waste reduction, and lean manufacturing emerged. The concept of reconfigurable manufacturing (RMS) has since emerged, aiming to achieve changeable functionality and scalable capacity by allowing quick adjustments to machine components, cells, or material handling units. RMS is seen as potentially more cost-effective in the long run compared to FMSs, though it requires significant changes in hardware and software. The chapter reviews recent research on manufacturing system flexibility, its measurement, and impact, and introduces the concept of a manufacturing system life cycle. It also compares the characteristics and prerequisites of FMSs and RMS, highlighting the importance of human-machine integration and the role of people in various manufacturing paradigms. Finally, it discusses the industrial and research challenges associated with these paradigms.