'The Art of Riding' series are by Baron Hans von Blixen-Finecke, and Christopher Bartle does most of the riding.

I have just been concentrating on turn on the forehand and leg yield so far (from the tapes), and it works so well. The instructions for leg yield go something like;

As you come around the corner move your seat laterally across the saddle and turn down the diagonal.
Use your inside leg on the hind leg button to ask for one crossing of the inside hind leg to bring the horse parallel to the side of the school, and give with the outside rein to allow the hind leg to cross,
Each time the inside shoulder moves back apply the inside leg and outside rein to continue in leg yield.
Use your outside leg on the foreleg button to limit excess sideways movement.
Start with two steps sideways then two steps forward, stop and reward the horse.
When this is going really well in walk proceed to trot.
Some horses find crossing both front and hind legs difficult in walk. This will improve in trot.

Well Bella isn't one of them! She glides across in walk, crossing beautifully, and feels better than some of the horses in the video look, in walk. I think it's because of the balance work that she's already done from 'Riding with the Clicker'. She instantly understood and reponded to my outside leg on the foreleg button, and our angle is now perfect.

Baron Blixen-Finecke also says that lateral flexion should be the result of giving the outside rein in the movement, to allow the flexion to happen, not asking for flexion with the inside rein, which is what I had been doing, and this works SO much better.

I always thought that leg yield was a rather basic, slightly clumsy looking introduction to lateral work, but this feels absolutely wonderful - the way I was expecting half pass to feel. It's all SO EXCITING!!! I can't wait to see what half pass feels like!!!!!

One of the many, many things I really appreciate about doing this with the clicker is that this lovely balance that we keep finding is so addictive that I want to hang onto it and experience more, more, more, now, now, now, but I can't. If I want to keep getting more I must click and let it go as soon as it feels perfect, and that must be right. It would be too much too soon to hang onto it at this stage, too hard for Bella, and this way she enjoys all the benefits of finding this perfect balance without the drawbacks of having to work really, really hard to keep it for any length of time.

I KNOW that keeping on finding this beautiful balance and then letting it go again immediately is exactly the right thing to do, but it would take an awful lot of self discipline to keep on doing it without the clicker to MAKE me do the right thing!