Oil, gas, and other types of underground pipeline are critical components of civil infrastructure. Detecting the presence of corrosion which may cause a pipeline to fail is a major challenge. This important book reviews key research on understanding corrosion processes and methods for detecting corrosion, including magnetic flux leakage, the close interval potential survey method, the Pearson survey method, and in-line inspection techniques. Part one covers: basic principles for corrosion in underground pipelines, AC-induced corrosion of underground pipelines, significance of corrosion in onshore oil and gas pipelines, numerical simulations for cathodic protection of pipelines, and use of corrosion inhibitors in managing corrosion in underground pipelines. Part two describes methods for detecting corrosion in underground pipelines, such as: magnetic flux leakage, close interval potential surveys (CIS/CIPS), Pearson surveys, in-line inspection, and use of both electrochemical and optical probes.