"This document@ intended for the Engineed Technician newly involved with welding@ describes the occurrence of the common weld discontinuities from both the metallurgical and process standpoints. The discontinuities are delineated in terms of their morphology in the weld on both a macroscopic and microscopic scale and the relationship of the NDT method for discontinuity revelation is described in terms of the discontinuity characteristics. The causes and cures for the many discontinuity types are outlined in an attempt to help the reader with the pragmatic and practical aspects of dealing with discontinuities. The codes and standards relationship to the acceptance levels for discontinuities is treated in a general fashion. The newer concepts of ""fitness-for-services"" are introduced and the near-future techniques for treating discontinuities are discussed."