1. Introduction to Polymeric Aerogels 2. Physical Processes to Obtain Gels and Hydrogels from Natural Polymers 3. Chemical Processes to Obtain Gels and Hydrogels from Natural Polymers 4. Green Processes to Obtain Gels and Hydrogels from Natural Polymers 5. Processes to Obtain Aerogels from Natural Polymers 6. Natural Polymer Gels, Hydrogels and Aerogels for Biomedical Applications 7. Natural Polymer Gels, Hydrogels and Aerogels for Absorbent Applications 8. Natural Polymer Gels, Hydrogels and Aerogels for Energy Saving Applications 9. Natural Polymer Gels, Hydrogels and Aerogels for Filtration Applications 10. Natural Polymer Gels, Hydrogels and Aerogels for Sensing Applications 11. Natural polymers, Silica and Carbon-based Aerogels: Catalytic Applications in Fine Chemical Synthesis. An Overview 12. Green processes to obtain seaweed polysaccharides based functional hydrogel & aerogel membranes for potential health and separation applications 13. Preparation and applications of aerogels-energy storage applications 14. Preparation and applications of aerogels-energy storage applications 15. Gels, hydrogels, and aerogels for absorbent applications 16. Synthesis and characterization of biopolymer aerogels for biomedical applications 17. Natural Composite Gels, Hydrogels, and Aerogels for Sensing Applications