This Reprint provides an overview of recent advances in polymeric membranes, focusing on their preparation, functionalization, and applications in water treatment, environmental remediation, energy conversion and storage, and biomedical technologies. Contributions cover membrane design and modification strategies, sustainable fabrication methods, enhanced selectivity and stability, and the integration of functional or bioactive materials. The Reprint highlights the versatility of polymeric membranes and their potential impact for industrial, medical, and environmental applications.