In recent years, considerable attention has focused on biological applications of the atomic force microscope (AFM), in particular on high-resolution imaging of individual biological molecules and on the measurement of molecular forces under near-physiological conditions. The detection of intermolecular forces in the piconewton range has paved the way to investigate details on structural parameters of the binding pockets and the energy landscapes of many biomolecular interactions. The capability of AFM to resolve nanometer-sized details, together with its force detection sensitivity, led to the development of molecular recognition imaging. By a combination of topographical imaging with force measurements, receptor sites are localized with nanometer accuracy. Topography and recognition of target molecules are thereby simultaneously mapped. Thus the AFM can identify specific components in a complex biological sample and retain its high resolution in imaging.