The book "Mechanical Response of Composites" offers a comprehensive analysis of the mechanical properties of composite materials and their reactions under various loads. It addresses the challenges of predicting material properties and the necessity of a well-planned testing program to ensure the performance and durability of composite structures. A central concept of the book is the Building Block Approach, which allows for minimizing technological risks through the incremental testing of smaller samples. This methodology promotes cost-effective development by creating a synergy between testing and analysis. By employing advanced computer-based models, the need for extensive mechanical testing is reduced, leading to significant cost savings. The authors, including Pedro P. Camanho and C. G. Dávila, contribute their expertise to guide readers through the complex aspects of composite engineering.