In the last years, Atomic Force Microscopy (AFM) has become a powerful tool not only to study the surface morphology but also the nanomechanics of all kind of samples. In this paper, the applicability of this technique is reviewed and its basic aspects of operation, advantages and drawbacks of using the AFM probe as a picoindenter (Force Spectroscopy mode, FS-AFM) are discussed. The patents concerning picoindentation measurements are discussed in the text and special attention is paid to measurements performed on hard materials as ceramics, as they have not been as thoroughly reviewed in the literature as in the case of soft matter. The possibilities of AFM in the nanomechanics field include the quantitative determination of the Young's modulus (E) and the transition force from elastic to plastic deformation regimes, the measurement of adhesion forces and deformation mechanisms while applying vertical forces in the range from tens of pN to μN.