Flexible and reconfigurable manufacturing systems are new paradigms aiming to achieve cost-effective and rapid system changes as needed. Reconfigurable Manufacturing Systems (RMS) incorporate principles of modularity, integrability, flexibility, scalability, convertibility, and diagnosability. RMS offers customized flexibility on demand, while Flexible Manufacturing Systems (FMS) provide generalized flexibility for anticipated variations. The characteristics of these paradigms are outlined and compared. The concept of manufacturing system life cycle is introduced, along with the main types of flexibility and their contrast with reconfiguration aspects, including hard and soft reconfiguration. The types of changeability and transformability of manufacturing systems, their components, and factories are discussed, along with their enablers and comparisons with flexibility and reconfigurability. The importance of harmonized human-machine systems is highlighted, and the role of people in various manufacturing paradigms is illustrated. Industrial and research challenges are discussed. Manufacturing systems have evolved from job shops to high-volume, low-variety dedicated lines. In the 1980s, flexible manufacturing was introduced to meet mass customization and responsiveness needs. FMSs were developed for mid-volume, mid-variety production, using similarities in design and manufacture to achieve economy of scope. FMSs are more robust but have high initial costs. In the 1990s, optimality, agility, waste reduction, quality, and lean manufacturing became key drivers for global competitiveness. Reconfigurable manufacturing emerged to achieve changeable functionality and scalable capacity. It proposes systems where components, machines, cells, or material handling units can be added, removed, modified, or interchanged as needed. While fully reconfigurable systems do not yet exist, they are the focus of major research efforts, especially in hardware and machine control. Proponents believe reconfigurable systems can offer cheaper long-term solutions by increasing system life and utility. Hardware reconfiguration requires changes in software, adding complexity to products, processes, systems, and enterprises. This paper reviews recent research on manufacturing system flexibility and its measurement and impact. Various types of flexibility are presented, along with their correspondence to reconfiguration aspects. The characteristics and prerequisites of reconfigurable manufacturing systems are overviewed. The concept of a manufacturing system life cycle is introduced, linked with flexibility and reconfigurability. Expert views on the comparison between flexible and reconfigurable manufacturing are presented.Flexible and reconfigurable manufacturing systems are new paradigms aiming to achieve cost-effective and rapid system changes as needed. Reconfigurable Manufacturing Systems (RMS) incorporate principles of modularity, integrability, flexibility, scalability, convertibility, and diagnosability. RMS offers customized flexibility on demand, while Flexible Manufacturing Systems (FMS) provide generalized flexibility for anticipated variations. The characteristics of these paradigms are outlined and compared. The concept of manufacturing system life cycle is introduced, along with the main types of flexibility and their contrast with reconfiguration aspects, including hard and soft reconfiguration. The types of changeability and transformability of manufacturing systems, their components, and factories are discussed, along with their enablers and comparisons with flexibility and reconfigurability. The importance of harmonized human-machine systems is highlighted, and the role of people in various manufacturing paradigms is illustrated. Industrial and research challenges are discussed. Manufacturing systems have evolved from job shops to high-volume, low-variety dedicated lines. In the 1980s, flexible manufacturing was introduced to meet mass customization and responsiveness needs. FMSs were developed for mid-volume, mid-variety production, using similarities in design and manufacture to achieve economy of scope. FMSs are more robust but have high initial costs. In the 1990s, optimality, agility, waste reduction, quality, and lean manufacturing became key drivers for global competitiveness. Reconfigurable manufacturing emerged to achieve changeable functionality and scalable capacity. It proposes systems where components, machines, cells, or material handling units can be added, removed, modified, or interchanged as needed. While fully reconfigurable systems do not yet exist, they are the focus of major research efforts, especially in hardware and machine control. Proponents believe reconfigurable systems can offer cheaper long-term solutions by increasing system life and utility. Hardware reconfiguration requires changes in software, adding complexity to products, processes, systems, and enterprises. This paper reviews recent research on manufacturing system flexibility and its measurement and impact. Various types of flexibility are presented, along with their correspondence to reconfiguration aspects. The characteristics and prerequisites of reconfigurable manufacturing systems are overviewed. The concept of a manufacturing system life cycle is introduced, linked with flexibility and reconfigurability. Expert views on the comparison between flexible and reconfigurable manufacturing are presented.