This edited book provides knowledge about hemicelluloses biorefinery approaching production life cycle, circular economy, and valorization by obtaining value-added bioproducts and bioenergy. A special focus is dedicated to chemical and biochemical compounds produced from the hemicelluloses derivatives platform. Hemicelluloses are polysaccharides located into plant cell wall, with diverse chemical structures and properties. It is the second most spread organic polymer on nature and found in vast lignocellulosic materials from agro and industrial wastes, therefore, hemicelluloses are considered as abundant and renewable raw material/feedstock. Biorefinery concept contributes to hemicelluloses production associated with biomass industrial processes. Hemicelluloses are alternative sources of sugars for renewable fuels and as platform for chemicals production.