AbstractThe three main types of chemical components in wood are cellulose, hemicellulose, and lignin. These three components have rather different physical and chemical characteristics. In some respects, the three types of materials can be described as “incompatible.” However, most of the biomass existing on the planet depends on their successful interactions. It can be useful to think of wood as being a natural composite structure. Concepts related to composites also are useful as we envision possible new and improved uses of wood-derived materials.