Plant cell walls are intricate structures that define cell shape, strength, and interactions with the environment. In this session, the biosynthesis and organization of cellulose, hemicellulose, pectin, and lignin in primary and secondary walls will be explored. Wall remodeling during growth, development, and stress adaptation will be addressed by experts. Case studies will feature the role of cell walls in pathogen resistance and mechanical support. Progress in genetic engineering to alter wall composition for biofuel production and enhanced digestibility will also be addressed. The session will highlight the industrial and agricultural value of cell wall biology, connecting molecular understanding to useful applications in renewable energy, paper manufacture, and crop improvement.