Societies produce large amounts of biomass waste from farming, logging, industry, and cities. This waste poses disposal problems, but also presents opportunities for utilization. The book covers waste management, materials science, and sustainable tribology. It gives a complete framework for turning different types of biomass waste into high-performance, eco-friendly tribological components. This discussion goes beyond standard recycling methods and looks at chemical and physical valorization techniques like pyrolysis, hydrothermal carbonization, and chemical modification that are used to turn agricultural, food, and industrial bio-waste into useful resources. These materials are then used to make the next generation of green lubricant base stocks, friction modifiers, and anti-wear additives. The main part of the book goes into the Bio-Tribology and Tribochemistry of these materials, explaining the exact processes, such as surface reactions and tribofilm formation, that bio-char, bio-oils, and their derived nanomaterials use to reduce friction and wear. It also gives practical methods for making stable and effective bio-lubricants, which will help researchers and engineers close the loop on the circular bioeconomy and lower the environmental impact of mechanical systems and looks at how combining modern valorization technologies with AI and machine learning will speed up the shift to a truly circular economy.