Increasing energy demand due to the depletion of fossil fuels and the growth of the human population has prompted the search for renewable and sustainable energy feedstocks. Renewable and green biofuels, e.g., biodiesel and bioethanol, are touted as promising surrogates for fossil fuels. The first generation of biofuel feedstock is mainly derived from food sources, e.g., rapeseed oil and sugarcane, whereas second-generation feedstock is derived from inedible and waste sources, e.g., waste cooking oil and forest biomass. However, these feedstocks have several limitations such as a serious impact on the food supply chain, low productivity, and complicated pre-treatment processes. On the other hand, strategic biofuel production from third-generation feedstock, namely, microalgae, macroalgae and larvae, has opened a new direction in the renewable biofuel industries. The third-generation feedstocks offer several benefits, such as fast growing rate, less utilization of arable land and less impact on the food versus fuel feud. Thus, this book is intended to highlight the potential of these new feedstock for biofuel production as well as other applications. The book is mainly divided into three parts, which cover the discussion of upstream and downstream processing technologies of microalgae, macroalgae and larvae. This book is useful to undergraduate and postgraduate students as well as researchers in the biofuel field to understand the overall process chain and conversion technologies of biofuels from third-generation feedstock.