A highly informative book, the third on the subject, lent to me by a good friend and knowledgabel colleague. It lays out the basics which allow me to look at new piece of equiptment and knowing two truth's in discover a third with certainty. It also cautions, rightly, that electricity is both unforgiving, and a non-respector of persons. Prevention out-weighs cure when delving with electricity, and allowing you to be certain with you accuracy.