Reconstructing the shape of an object from images is an important problem in computer vision that has led to a variety of solution strategies. This monograph focuses on photometric stereo, that is, techniques that exploit the observed intensity variations caused by illumination changes to recover the orientation of the surface. In the most basic setting, a diffuse surface is illuminated from at least three directions and captured with a static camera. Under some conditions, this allows to recover per-pixel surface normals. Modern approaches generalize photometric stereo in various ways; for...