This book contains 12 chapters. Chapter 1 focuses primarily on the fundamentals of nanocellulose, including general aspects on its structure, isolation, and characterization. Chapters 2-4 summarize the recent progress on assembly of nanocellulose into the macroscopic scale using state-of-the-art techniques. Chapters 5-13 cover the most advanced applications of nanocellulose in emerging areas, including superstrong materials, light management, electronics, energy storage, printed battery, water treatment, nanogenerator, and biomedicine. The book will appeal to upper undergraduate and graduate students through practicing researchers as a comprehensive reference on the subject of nanocellulose and its use in various fields.