Despite their desirable properties, the lack of good interfacial adhesion between fibers and matrix, low melting point, and water sensitivity make the use of natural fiber-reinforced composites less attractive. Surface roughness can be increased and moisture absorption is decreased by surface modification of natural fibers. Various methods have been explored in order to improve the compatibility between hydrophilic natural fibers and hydrophobic polymer matrices. Most of the chemical surface treatments of natural fibers involve silylation, acetylation, benzoylation, isocyanate treatment and polymer grafting. Although these treatments can alter the wettability of natural fibers, the appropriate handling and disposal of the large amounts of hazardous chemicals that is often involved is unattractive and an additional cost to the production. Surface modification of natural fibers by alternative green methods may surpass the chemical treatments. Efforts are now being focused on environmentally friendly methods to increase the compatibility between natural fibers and polymer matrices. This book comprehensively addresses surface modification of natural fibers to make them more effective, cost-efficient, and environmentally friendly. Topics include the elucidation of important aspects surrounding chemical and green approaches for the surface modification of natural fibers, the use of recycled waste, properties of biodegradable polyesters, methods such as electrospinning, and applications of hybrid composite materials.