This review article by Chuyang Y. Tang et al. focuses on the development and challenges of ultrathin polyamide membranes in water treatment applications. The authors highlight the importance of membrane-based separation for addressing the growing demand for freshwater, particularly in water treatment, desalination, solvent recycling, and environmental remediation. They discuss the advancements in manufacturing techniques, such as interfacial polymerization (IP), layer-by-layer (LbL) assembly, spin-coating, electrospray, inkjet printing, and dual-layer slot coating, which have enabled the creation of ultrathin polyamide membranes with enhanced water permeance and salt rejection. The review also addresses the limitations of these membranes, such as the "funnel effect" caused by the substrate membrane, which reduces the actual permeation rate. The authors propose potential solutions and future perspectives, emphasizing the need for further research to fully understand and optimize the performance of ultrathin polyamide membranes. They conclude by discussing the potential applications of these membranes in various fields, including organic solvent nanofiltration, gas separation, carbon capture, and wastewater treatment, and highlight the opportunities for novel membrane materials like aquaporins, aligned carbon nanotubes, and graphene-based membranes.This review article by Chuyang Y. Tang et al. focuses on the development and challenges of ultrathin polyamide membranes in water treatment applications. The authors highlight the importance of membrane-based separation for addressing the growing demand for freshwater, particularly in water treatment, desalination, solvent recycling, and environmental remediation. They discuss the advancements in manufacturing techniques, such as interfacial polymerization (IP), layer-by-layer (LbL) assembly, spin-coating, electrospray, inkjet printing, and dual-layer slot coating, which have enabled the creation of ultrathin polyamide membranes with enhanced water permeance and salt rejection. The review also addresses the limitations of these membranes, such as the "funnel effect" caused by the substrate membrane, which reduces the actual permeation rate. The authors propose potential solutions and future perspectives, emphasizing the need for further research to fully understand and optimize the performance of ultrathin polyamide membranes. They conclude by discussing the potential applications of these membranes in various fields, including organic solvent nanofiltration, gas separation, carbon capture, and wastewater treatment, and highlight the opportunities for novel membrane materials like aquaporins, aligned carbon nanotubes, and graphene-based membranes.