The book serves as a comprehensive guide to the key principles, strategies, and innovations that will define the future of sustainable product design in a circular economy. This book explores how modularity, repairability, and recyclability transform industries, creating opportunities for longer-lasting products, reducing waste, and improving resource efficiency. By integrating these principles, businesses and designers can craft products that support a regenerative, sustainable system of production and consumption. The book presents a roadmap for incorporating these principles into product design through a series of chapters, offering real-world case studies, technological innovations, and best practices. The book begins with an introduction to the foundational concepts of the circular economy, emphasizing the critical need for sustainable design. It further explain the shift from traditional linear models to circular approaches prioritizing resource conservation, waste minimization, and product lifecycle extension. Readers will understand how modularity, repairability, and recyclability form the cornerstone of this shift, enabling products to be designed for longevity and reuse rather than disposal