The use of biologically derived polymers is emerging as an important component of sustainable economic development. Technical lignins, derivatives from naturally occurring lignin polymers in woody plants, are generated commercially in large quantities -- up to 70 million tons world-wide annually. Besides being burned as fuels, only a small percentage of these lignins are used for various applications because technical lignins present relatively unpredictable structural characteristics and are therefore unreliable feedstocks to make products with consistent and satisfactory quality. Over the past two decades, there has been great progress in the research and commercialisation of lignin-based products and processes that add significant value to lignins. This book provides critical reviews and the latest research results relating to selected fields of lignin structural analysis and applications. Featuring the significant advances in selected topics of the lignin research field, this reference book is for college students and scientists with the intent of promoting further research and innovations in this specialised field.