Progress in nanotechnology and nanoscience requires the appropriate characterization methods for studies of materials and devices at the sub-100 nm scale. Atomic force microscopy (AFM) offers high- resolution visualization of surfaces and it is often employed for imaging of individual molecules and manipulation of nanometer-scale objects. This method is also widely used for measurements of surface roughness and quantitative examination of technologically important nanoscale-structures. Despite broad applicability of AFM instruments, imaging and probing of mechanical and electric surface properties at the sub-100 nm scale is not yet the routine procedure. Several factors influencing these functions such as geometry of probes, operation modes, detection sensitivity and thermal drift will be discussed in more details. Practical examples of imaging with atomic- and molecular-scale resolution will be given and analyzed from different viewpoints.