Did I mention that I recommended two books to this curious student-to-be?
I certainly think that reading F.M. Alexander is key if you want the true essence of the Technique. Everything else is a distillation and interpretation. Try his book, The Use of the Self. If you only read the first chapter, “Evolution of a Technique,” you would have the essence of the work.
You can find The Use of the Self at AmSAT* Books online.
For clear pictures and very clear, practical guidance, I like Glynn MacDonald’s book:
Curious to hear if you read these; let me know if they are helpful!
*The American Society for the Alexander Technique