This book provides a comprehensive overview of the current state-of-the-art science and technology related to polysaccharide-based 3D-engineered materials, highlighting their fabrication and specific environmental and advanced technological applications. Polysaccharide-based 3D-engineered materials have attracted global interest as sustainable and renewable alternatives to synthetic polymers for diverse and advanced applications. This book provides researchers and scientists with the latest and up-to-date knowledge related to the fabrication and applications of 3D-engineered polysaccharide materials, including hydrogels, 3D/4D printing, aerogels, foams, sponges, and other 3D scaffold materials. This book aims to address the primary issue currently faced in the market. Although several books are available, there is still no comprehensive scientific reference that systematically covers all aspects of fabricating engineered 3D polysaccharides and their nanocomposite formulations. So, this book solves the potential deficiencies in published books in the market. We provide specialized and up-to-date knowledge not extensively covered in existing publications, addressing the needs of researchers, practitioners, and industry professionals interested in advancing their understanding and advanced applications, such as environmental remediation and advanced engineered applications.