It is a very generic and fundamental system, it can be applied to just about any activity or skill. While many other people have contributed before and after him, and many more will do so in the future, it is probably safe to say that without him we wouldn't have a system like the Alexander Technique. Alexander Technique is usually learned by taking a series of lessons. Common movements, postures and activities are used to teach the principles of the technique. The teacher uses verbal explanation, visual feedback and touch to guide the student.
Lessons can be quite intensive, and so they usually last only about half an hour.