Abstract: A probe module for atomic force microscopy has a substrate (33) and a deflectable cantilever probe (4) projecting from it. In the head of the atomic force microscope the probe is mounted with its axis perpendicular to the sample surface, e.g. so as to carry out shear force microscopy or transverse dynamic force microscopy. The cantilever probe (4) has a reflective surface (43) which is directed back up along the probe so that movement of the probe tip can be tracked using a light beam arrangement which in itself may be conventional. By this means, AFM procedures in perpendicular modes can be carried out using AFM heads requiring little modification from the conventional near-parallel mode arrangement. The probe may also be used in tapping mode to investigate sidewall features on a sample surface.