The first time I came across Marvin was when I was writing my Masters exam, I did not know anything about what was required to pass this exam, so I did a search and came across Orderline.com and this is when I found "Masters Electrician License Workbook and Cd. I used this product, but had some problems navigating through the info, so I called the number on the back of the book, and someone picked up the phone and it was Marvin. I was surprised - I asked a few questions, and he helped me out- this was amazing to me. I passed that exam without taking any courses, since then I have referred friends and people that work for electrical companies, owners and apprentices to use his products, lets face it sometimes the electrical code can be complicated. In my opinion Marvin Rosenberg is a silver lining when it comes to electrical knowledge and information in a simplistic way that any electrician can understand.