The amendments of this third English edition with respect to the second one concern beside some printing errors the replacement of some pictures in part D by more modern ones and updating the list of stand ards to the state of the fourth German edition. J OSEF KRAUTKRÄMER Cologne, January 1983 Preface to the Second Edition This seeond English edition is based on the third German edition. In view of most recent teehnologieal advanees it has beeome neeessary in many instanees to supplement the seeond German edition and to revise some parts completely. In addition to piezo-eleetric methods, others are now also extensively diseussed in Chapter 8. As for the intensity method, ultrasonie holo graphy is treated in the new Seetion 9. 4. In Part B, for reasons of syste maties, the resonanee method has been ineluded under transit-time methods. It appeared neeessary to elaborate in greater detail the defini tion of the properties of pulse-echo testing equipment and their measure ments (10. 4). The more recent findings of pulse speetroscopy (5. 6) and sound-emission analysis (12) are mentioned only in passing because their significanee is still controversial. Apart from numerous additions, partieularly those coneerning automatie testing installations, Part C also eontains a new chapter whieh deals with tests on nu eIe ar reactors (28), as weIl as abrief diseussion of surfaee-hardness tests (32. 4). It beeame impossible to include a critieal analysis of the principal standards in Chapter 33.