Book excerpt: This book explores the use of biomass as an energy source and its application in energy conversion technologies. Focusing on the challenges of, and technologies related to, biomass conversion, the book is divided into three parts. The first part underlines the fundamental concepts that form the basis of biomass production, its feasibility valuation, and its potential utilization. This part does not consider only how biomass is generated, but also methods of assessment. The second part focuses on the clarification of central concepts of the biorefinery processes. After a preliminary introduction with industrial examples, common issues of biochemical reaction engineering applications are analysed in detail. The theory explained in this part demonstrates that the chemical kinetics are the core focus in modelling biological processes such as growth, decay, product formation and feedstock consumption. This part continues with the theory of biofuels production, including biogas, bioethanol, biodiesel and Fischer-Tropsch synthesis of hydrocarbons. The third part of this book gives detailed explanations of preliminary notions related to the theory of thermodynamics. This theory will assist the reader when taking into account the concepts treated in the previous two parts of the book. Several detailed derivations are given to give the reader a full understanding of the arguments at hand. This part also gives literature data on the main properties of some biomass feedstock. Fundamentals of Biofuels Engineering and Technology will be of interest not only to academics and researchers working in this field but also to graduate students and energy professionals seeking to expand their knowledge of this increasingly important area.