Metals, minerals, and plastics are all subject to the destructive power of corrosion — affecting billions of dollars of repair and replacement costs per annum. It is not, however, a one-sided battle. Public and private sectors combat corrosion by pouring billions of dollars into research aimed at developing advanced corrosion-resistant materials, corrosion-resistant paints and coatings, and corrosion inhibitors. Corrosion is an interfacial phenomenon, occurring at solid surfaces in contact with gases or liquids. Although it often has macroscopic consequences, corrosion typically begins at the atomic level. These factors make corrosion processes ideal candidates for study via in situ scanning probe microscopy (SPM), a highly sensitive surface technique that can be utilized in the presence of a wide range of corrosive solutions and gases. The versatility of in situ SPM enables direct, real-time observation of corrosional processes with atomic or near- atomic resolution, often providing valuable kinetic information as well as important structural data.