The research focus of this project was on a fundamental understanding of the intrinsic properties of energetic crystals (molecular and crystalline attributes/mechanisms) that govern their insensitivity at conditions relevant to shock wave induced chemical decomposition. Some aspects of this effort were also relevant to thermal loading. The combination of well-characterized shock wave and static compression experiments on insensitive energetic single crystals and different types of measurements were used to gain insight into the molecular and crystalline mechanisms of interest. To the best of our knowledge, the shock wave measurements carried out on insensitive high explosive (IHE) single crystals represent the first such measurements. Shock wave experimental capabilities central to this research effort were also utilized for developing a research collaboration with NSWC-IH.