The impact sensitivity of explosives is a critical issue because large amounts of energy can be released quickly due to mechanical impacts. Shock, thermal or electric stimuli also produce the same effect. These materials are controllable storage systems of chemical energy that are frequently stored, transported, and broadly used. Therefore, a comprehensive understanding of the sensitivity of an explosive is paramount, for example, for reducing its sensitivity, thus increasing safety. Energetic materials are usually molecular solids made of polyatomic molecules arranged in complicated crystal structures. This class of materials, which also includes propellants and pyrotechnics, is most valuable when combining low sensitivity (i.e., they are safer) and high energy content. However, good performance of an energetic material usually corresponds to increased sensitivity. These two apparently incompatible requirements demand a more significant fundamental understanding of the molecular origins of the sensitivity of energetic materials either known or to be developed.