What I’m talking about is the interplay between hook, and body motion. 
I will try to explain:

The road to great golf goes from slice, to hook, then to great golf.  I first heard Hank Haney say that at a teaching Summit in Dallas many years ago.  I have used that theme in my teaching ever since, to great success if I may say so.  He went on to say that a slicer will never improve much, because the harder they hit, the more it slices.

I would add, that if you slice, then you had better restrict the body motion through the shot, because again, it would make you slice more.  Also, slicers usually compensate by aiming left, and swinging even more left (righty golfer).  Now you have 2 problems! Enough said. Learn to not slice, by learning to hook.  In some ways you are being inoculated with a mild form of the disease, to insure you will be immune!  More on that later.

Once a golfer can hit a hook by squaring club by rotating the forearms, only then can great weight shift and hip turn be introduced, to then take away the hook.  In essence, you are still hooking, but hooking LATER.  Another word for this is lag.

When the dynamic play between hook and body motion are properly working, great ball striking is the result.

How to hook: The following information is for slicers only (85% of the golfing population). Hookers can skip to the next part.

Next time you drive in your car, and have to take a sharp turn to the left, you are making the motion to learn a hook; both forearms are rotating to the left.  This makes the face also rotate, resulting in the face close-ing through impact.  Do it soon enough, and the ball will hook.

I sometimes tell my students that I am a traffic cop, and this is a left-turn-only zone.  If it goes to the right, you’ll get a ticket.  Turn left, and do it for a few weeks before going to part 2.  The best transfer athletes from other sports to golf, is racecar drivers; I believe the reason is that they know how to turn left.

How to get rid of the hook:

You might say, you have been inoculated with a mild form of the disease, to make you better later.  Certainly a big hook is not desired on the course, it is only a step in the development process.

To get rid of it, shift your hips to the left, as you turn them in a rotary fashion.  (Turn into your left leg).  This motion carries the hook motion more to the left, causing it to happen later. Back to Mario Andretti, you still want to turn left, but now do it at the last moment possible.  The result is that magical feeling called lag.

This is the process, in the simplest form I can put it, to develop a quality golf striking motion.  Good Luck.