Scanning probe microscopes can probe a variety of quantities character
izing surfaces. This overview paper describes techniques applicable in
an ambient environment and having the power to distinguish different
materials: the scanning force and friction microscope and the scanning
near-field optical microscope combined with a spectrometer. The basic
operating principles of these two microscopes are described. Selected
experiments point to possible future applications: we discuss scannin
g force and friction microscopy of ZnSe on GaAs and of Na, K-ATPase an
d near-field optical microscopy of a grating and of micropores.