Biodiesel is a renewable, clean-burning diesel replacement that is creating jobs, improving fuel security and providing cleaner air for us to breathe. Biodiesel is commonly made from vegetable oils such as canola oil, animal fats (tallow) or recycled greases such as used cooking oil. Other feedstocks being developed include algae, pomgania trees, jatropha, camelina and dry land juncea. The feedstock containing the fatty acid is combined with alcohol which causes the condensation of water molecules, leaving behind the rich, pure fatty acids. The process used to convert these oils to Biodiesel is called transesterification. The largest possible source of suitable oil comes from oil crops such as rapeseed, palm or soybean. Most biodiesel produced at present is produced from waste vegetable oil sourced from restaurants, chip shops, industrial food producers such as Birdseye etc. Waste vegetable oil can often be sourced for free or sourced already treated for a small price. Biodiesel has many environmentally beneficial properties. The main benefit of biodiesel is that it can be described as carbon neutral. This means that the fuel produces no net output of carbon in the form of carbon dioxide (CO2). Biodiesel is meant to be used in standard diesel engines and is thus distinct from the vegetable and waste oils used to fuel converted diesel engines. Biodiesel can be used alone, or blended with petrodiesel in any proportions. Biodiesel blends can also be used as heating oil. This book, Biodiesel - Feedstocks, Production and Applications, emphases on the advances of biodiesel systems from the production of feedstocks and their processing technologies to the comprehensive applications of both by-products and biodiesel. It will be of invaluable tool for academics, researchers, scientists and technologists.