Which properties of rock are important in the context of blasting, and how do we measure them? The two questions are not easily answered, because the physical and mechanical processes involved in the blasting process are not entirely clarified and understood. However, it is obvious that the structural characteristics of the rock mass and the strength and fracture properties of its ingredient rocks are important to know as a basis for understanding the blasting process. The following brief introduction to some selected areas of rock mechanics and geological engineering is intended to give a person not previously acquainted with these subjects a feeling for the way the rock materials and rock masses may react to the forces released by the detonation of explosive charges in drillholes.