Facing unprecedented global water scarcity, desalination has evolved from a strategic option to an urgent necessity. However, conventional technologies remain constrained by high energy requirements, membrane fouling, limited tolerance to hypersaline conditions, and environmental footprints. This volume presents frontier solutions that transcend these barriers. Bridging materials science, process engineering, and sustainable system integration, the book explores next‑generation membrane materials, from polyamide composites to graphene oxide, biomimetic aquaporins, and zinc‑oxide‑enhanced platforms, alongside advanced processes such as forward osmosis, pervaporation, and vacuum membrane distillation. It demonstrates how machine learning can revolutionize nanofiltration design and fouling prediction, while functionalized biochar offers low-cost pretreatment to prevent scaling. Critically, the book addresses energy‑autonomous and zero-discharge desalination: recovering waste heat from ship exhaust, stabilizing photovoltaic‑driven reverse osmosis under intermittent power, and integrating electrochemically assisted anaerobic digestion to produce biogas and recover added‑value compounds from waste streams. By uniting breakthroughs in hydrophilic and antimicrobial membranes, hybrid electrocoagulation‑membrane systems, and renewable‑powered operation, this work provides a roadmap toward efficient, resilient, and circular desalination. Ideal for researchers, engineers, and graduate students, it transforms the vision of sustainable freshwater production into an actionable reality.