In this talk, we will first review the physics and mechanics of fluid driven fractures with the aim of engineering hydraulic stimulation in practice. In particular, based on theoretical modeling and comparisons with experiments, we will clarify a number of points raised in the literature (stability of the fracture propagation, fracture initiation, solid and fluid non-linearities, fracture height containment, etc.). We will also argue for the importance of verification of numerical models against available semi-analytical solutions for simple fracture geometries. Finally, we will discuss the process of multi-stage fracturing. We will show how a combination of modeling and field observations can help in better engineering this type of operations.