The increasing number of terrorist attacks in recent times has increased the importance of developing novel materials and structures with improved blast resistance, low weight, and high strength. The research described in this book goes along these guidelines. Our focus is in the development of materials and structures based on experimental and numerical investigation of their performances under blast and fragment loading. Experimental and numerical investigations are used to understand the failure modes of structures and the influence of the microstructure in the behavior of materials. This knowledge is required to validate and develop constitutive models to be used in the development of high performance materials and structures.