The chapter sets the scene for the book by tackling some of the fundamental issues with biorefineries. The biorefinery cannot just be a processing facility which utilises biomass without any concern for the chemical methods being used. So the first section of this chapter covers the fundamental aspects of green chemistry and how they can be incorporated into future biorefineries. There has been much discussion and debate on the biorefinery concept and what it actually means. The second section in the chapter covers the main aspects of biorefinery systems including the two platform concept. The last section of the chapter focuses on the current and potential uses of oil crops that are produced within Europe.