This chapter shows the utilization of in situ atomic force microscopy (AFM) imaging to probe interactions between biomolecules and crystal faces and to provide a brief review of recent advances in dening the underlying physical principles that are responsible for the control of biomineral formation through real-time characterization. The mechanical components of the scanner are next to the AFM base, which houses all the controlling electronic circuits of the system. Solution can penetrate to the scanner tube by letting it dwell too long under the sample puck, and consequently, crystallites form as water naturally evaporates. in situ AFM can be used to observe the molecular scale growth modication of surface steps by chiral molecules and to reveal the mechanism by which the changes in small scale are translated into bulk crystal habit. The rough nature of the step edge is originated from the thermal uctuations associated with the growing surface.