Recently, we have studied the interaction of reactive adsorbates H, C, O, and S with Ni and Cu surfaces by scanning tunneling microscopy (STM). In this paper, we briefly illustrate and discuss how such studies provide significant insight into the understanding of dynamic surface processes such as adsorbate-induced restructuring, surface reactions, and adsorbate-adsorbate interactions. The STM results demonstrate that there is a strong coupling between the chemisorption/reaction process and the distortion of the metal surface.