The significance of environmental sustainability is undoubtedly important for life and survival of mankind. The emerging material and product world is now searching for material, structure, and processes that are supportive of the environment. The materials rendering the desired performance without harming the environment are viable for the sustainable growth of the industry. Therefore, montmorillonite clay becomes an attractive material in making various products. The book chapters are written to provide scientific understanding and knowledge to scholars, students, faculty members, and laboratory and industry workers of the subject of montmorillonite clay, including its structure and properties, use in composite, industrial application, and testing and evaluation using analytical techniques. The book's contents signify how important montmorillonite clay is in material and product development in the current industrial marketplace.