Book excerpt: This book provides an updated and detailed overview on the recent developments of bioethanol technology. It looks at the historical perspectives, chemistry, sources and production of ethanol and discusses biotechnology breakthroughs and promising developments, its uses, advantages, problems, environmental effects and characteristics. In addition, it presents information about ethanol in different parts of the world and also highlights the challenges and future of ethanol. The first edition of this book was published as a SpringerBriefs in 2013. Since then, many new developments have taken place in the last six years. This new edition will highlight the evolution in bioethanol development from first-generation production to the futuristic fourth-generation bioethanol production, the various constraints and challenges involved, and the scope for development. This book caters to the audience who are interested in alternative transportation fuels which are both biodegradable and sustainable to the environment.