This book is intended to help satisfy an urgent requirement for up-to-
date comprehensive texts at graduate and senior undergraduate levels on
the subjects in non-destructive testing (NDT). The subject matter here
is confined to electrical and magnetic methods, with emphasis on the
widely used eddy current and magnetic flux leakage methods (including
particle inspection), but proper attention is paid to other techniques,
such as microwave and AC field applications, which are rapidly growing
in importance. Theoretical analyses relating to the various methods are
discussed and the depths of presentation are often governed by whether
or not the information is readily available elsewhere. Thus, for
example, a considerable amount of space is devoted to eddy current
theory at what the author considers to be a reasonable standard and not,
as usually experienced, in either a too elementary manner or at a level
appreciated only by a postgraduate theoretical physicist. The inclusion
of the introductory chapter is intended to acquaint the reader with some
of the philosophy of NDT and to compare, briefly, the relative
performances of the more important methods of testing.