Acoustic Emission (AE) is a naturally occurring phenomenon whereby external stimuli, such as mechanical loading, generate sources of elastic waves. AE occurs when a small surface displacement of a material is produced due to stress waves generated when there is a rapid release of energy in a material, or on its surface. This new book presents current research in the study of the theory and uses of acoustic emissions. Topics discussed include acoustic emission from rocks generated in the course of a variety of experiments; applying the acoustic emission technique to estimate the defect density and strength of adhesively bonded couplings and structural health monitoring of ships and offshore structures using acoustic emission testing.