Book excerpt: It is of great importance that both individual components and complete engineer ing assemblies and structures are free from damaging defects and other possible causes of premature failure. A whole series of inspection instruments and tech niques has been evolved over the years and new methods are still being developed to assist in the process of assessing the integrity and reliability of parts and assemblies. Non-destructive testing and evaluation methods are widely used in industry for checking the quality of production, and also as part of routine inspec tion and maintenance in service. Despite the obvious importance of the subject, and the fact that most of the inspection methods are based on well-established scientific principles, there is a dearth of publications suitable for use as texts in our universities and colleges. The whole area of non-destructive testing receives scant attention in many engineering degree and diploma courses in the UK and this may be a consequence of a shortage of student texts. The authors, in producing this basic text, hope that it will prove useful to students on engineering courses and, possibly, act as a stimulus for the more widespread introduction of the subject into curricula.