A probe assembly is for use in a scanning probe microscope. The probe assembly includes a carrier having a plurality of at least three substantially identical probes, each probe having a tip that is located on a plane that is common to the plurality of probe tips and that is movable from this plane. The assembly also includes addressing means adapted to select one of the plurality of probes for relative movement with respect to a majority of the remainder of the probes. Such an assembly, with its potential to facilitate rapid, perhaps automated, replacement of a used probe, lends itself to use in high-speed scanning apparatus.