The original program was customized to the athlete.
For example, you'd determine your goal (strength, mass, endurance etc.) and test your 1RM on say, 3-8 exercises.
You'd mail this away (no internet yet) and they'd mail you a custom 8 week program complete with how many reps and sets to do along with how much weight to use AND how long to rest in between sets.
It was beautiful, and worked better than anything I've ever tried. I would gladly shell out whatever they were asking for today if it were available.
I'm assuming it would be a HELL of a lot cheaper/faster now with the internet around.