Might be an unpopular opinion, but Mentzer actually was ahead of the game back then. I had seen interviews, clips, read second hand stories about him. But then last month when he was plastered all over the board, I looked for a free download of his work. He had the Heavy Duty system/book at (I believe) 68 pages. And about 20 of those were photos. And he had a nutrition book that was about 14 pages.
Reading these took one night. And he was really down to earth and common sense principled about his system. It made a lot of sense. I mean, you couldn't really disagree with it.
Now, that said.... I don't think the Heavy Duty is for everyone. Mainly for two reasons.
1) You need a training partner for each workout. Most of us train by ourselves on our own time. But you will need assistance.
2) The actual workout program for the chest, quads, and back would require you to reserve two different machines at once in a gym. That really doesn't go well because most gyms keeps their machines separate from their free weights. So after warming up on the incline, you would head to the pec deck, warm up there and then proceed with the first half of your superset which afterwards you would run back to the incline and pray no one had taken it. Same way with quads, warm up on leg press, then go to leg extensions, warm up there, do your working set, partials, 20 second lock out hold, and run back to the leg press hoping no one plopped down on it.
It's amazing after reading this that I thought back to the people that claimed they trained Heavy Duty style, when in fact they didn't. Rich Piana absolutely butchered the program when he talked about training "the Mentzer way". I wonder if any of those people actually read the book.
Taking into consideration his drug use, downward spiral (Tom Platz once claimed he came across Mentzer sleeping in a filthy gutter and then he came to the gym and started tearing his photos off the walls), I honestly believed that if had stayed clean and lived a bit longer that he would have refined the Heavy Duty even further to something even better. But we will never know.