Abstract: A scanning probe microscope includes probe moved into and out of engagement with a sample surface by a combination of deflections occurring within a fast actuator, having a relatively small range of motion, and a slow actuator, having a relatively large range of motion. When the deflection of the fast actuator is moved outside a predetermined range, in which such deflection is a linear function of applied voltage, the slow actuator is operated so that subsequent operation of the fast actuator can return the fast actuator to its predetermined range, Furthermore, when it is necessary to operate the slow actuator in this way, a scanning motion moving the sample surface past the probe is stopped until the probe is brought into a correct level of engagement with the sample surface, with the fast actuator deflected within the predetermined range.