I would have to agree with Mr. Fretwell. I have been providing instruction for several years, and the latest edition of Soares (version 9E) is absolutely the best publication I have ever read on grounding and bonding. The book is written by the International Association of Electrical Inspectors, who also sells a powerpoint publication to be utilized to teach the contents of the book.
Mu personal experience is the best (clear and descriptive) material available is published by them. They also provide 24 hrs of "Train-the-Trainer" education on the soares program as well as others.
All their material can be found at: www.IAEI.org
Discounts are available for members and this may be an additional incentive to join if you are a non-member.