Conversion of biomass into chemicals and biofuels is an active research and development area as trends move to replace traditional fossil fuels with renewable resources. By integrating processing methods with ultrasound and microwave irradiation into biorefineries, the time-scale of many operations can be greatly reduced while the efficiency of the reactions can be remarkably increased so that process intensification can be achieved. “Production of Biofuels and Chemicals with Ultrasound” and “Production of Biofuels and Chemicals with Microwave” are two independent volumes in the Biofuels and Biorefineries series that take different, but complementary approaches for the pretreatment and chemical transformation of biomass into chemicals and biofuels. The volume “Ultrasound” provides current research advances and prospects in mechanistic principles of acoustic cavitation in sonochemistry, physical and chemical mechanisms in biofuel synthesis, reactor design for transesterification and esterification reactions, lipid extraction from algal biomass, microalgae extraction, biodiesel and bioethanol synthesis, practical technologies and systems, pretreatment of biomass waste sources including lignocellulosic materials, manures and sludges for biogas production, vibration-assisted pelleting, combined chemical-mechanical methods, valorization of starch-based wastes and techno-economic methodology. Each of the 12 chapters has been peer-reviewed and edited to improve both the quality of the text and the scope and coverage of the topics. Both volumes “Ultrasound” and “Microwave” are references designed for students, researchers, academicians and industrialists in the fields of chemistry and chemical engineering and include introductory chapters to highlight present concepts of the fundamental technologies and their application. Dr. Zhen Fang is Professor in Bioenergy, Leader and founder of biomass group, Chinese Academy of Sciences, Xishuangbanna Tropical Botanical Garden and is also adjunct Professor of Life Sciences, University of Science and Technology of China. Dr. Richard L Smith, Jr. is Professor of Chemical Engineering, Graduate School of Environmental Studies, Research Center of Supercritical Fluid Technology, Tohoku University, Japan. Dr. Xinhua Qi is Professor of Environmental Science, Nankai University, China.