One of the techniques that Williams liked to use - especially for more advanced lifters or for lifters who are "built" for a certain lift - was something called "21s." And, no, these are not the 21s that are popular for bodybuilders.
Here's how real 21s work: On your major lifts (squats, benches, deads, overhead presses - whatever lift it is that you're trying to get stronger) you perform no more than 21 total reps for that lift in the workout. Using this technique you then train the lift rather frequently. Anywhere between 3 to 5 days per lift, for instance. (On deadlifts you might want to do less; the muscles of the lower back simply take longer to recover for most lifters.)
Let's say that you have a max squat that hovers somewhere in the 400 pound range. Using 21s your workout might go like this: 135 for 5 reps, 225 for 5 reps, 275 for 5 reps, 315 for 3 reps, 375 for 2 reps, 400 for 1 single. You then repeat this workout another 2 to 3 days during the week. Because the volume is so low on the lift, your body can handle the frequent training. Slowly increase the weight over the course of a few weeks, and before you know it your squat is better than ever.
Here is what a week of training might look like for a powerlifter trying to increase all his/her 3 lifts:
Monday: Squats: 21 reps, Bench Presses: 21 reps, chins for 5 sets of 5 reps, lying dumbbell triceps extensions for 3 sets of 10 reps
Tuesday: Bench Presses: 21 reps, Deadlifts: 21 reps
Wednesday: Squats: 21 reps, barbell curls for 3 sets of 10 reps, front plate raises for 3 sets of 10 reps
Thursday: Deadlifts: 21 reps, Bench Presses: 21 reps, bench dips for 2 sets of 20 reps
Friday: Squats: 21 reps
Saturday: Bench Presses: 21 reps
It's a shame you don't see more of this kind of lifting performed nowadays. Maybe it's not very popular because it's just too straightforward and basic. There's nothing glamorous about it, that's for sure. Of course, there was nothing glamorous about Jim Williams either, just a heaping mountain of mass and might. That's all.
May Jim Williams rest in peace. He deserves it. But may his training programs get more respect and more use by modern lifters. He deserves that as well.