This book highlights recent progress on the advancements toward optimization of major biorefinery processes, including biomass pretreatment and fractionation, saccharification of sugars, and conversion of sugars and lignin into fuels and chemical precursors. The continual improvement of these processes and their integration in the format of a modern biorefinery is paving the way for a sustainable bio-economy that will displace large portions of petroleum-derived fuels and chemicals with renewable substitutes. Written by leading researchers from academia and well-renowned industry professionals, this book provides a comprehensive review of various aspects related to the recent developments in biomass conversion and biorefinery, aimed at successfully implementing the circular economy principles in various industries.