I find it a bit difficult to recommend books on Alexander technique. There is a lot of good stuff on the web. I always say pick the most popular one on amazon. There are, no doubt many, many good books. This one is almost a pamphlet but quite good.
Understanding the Alexander Technique by Joan Diamond
How to Learn the Alexander Technique: A Manual for Students by Barbara Conable A primer for students of the Alexander Technique, a well-known method for improving freedom and ease of movement and physical coordination. This book provides the first authoritative account of William Conable's concept, Body Mapping, the study of how our ideas about our bodies affect our experience and movement. This concept is integrated with a lucid explanation of the Alexander Technique that clarifies and simplifies the task of teaching and learning the Technique. For the serious student you can’t beat this but it is probably not necessarily a beginner’s book. It has a fascinating history and culture you have to absorb to gain her precious insights into the technique.
There is a good bit of politics of the organization and Alexander’s struggles.
An Examined Life: Marjory Barlow and the Alexander Technique by Marjory Barlow (Author), Trevor Allan Davies (Contributor)
At the age of 17, Marjory Barlow began lessons in the Alexander Technique with her uncle F.M. Alexander. Seven decades later, she candidly revisits her personal experience of her uncle, and her passionate engagement with the Alexander Technique. In this series of searching conversations with fellow Alexander teacher Trevor Allan Davies, Marjory Barlow provides insights into the subtleties of an Alexander teacher's craft; the difficulties and resistance experienced by pupils of the work; the history and development of the Technique, and the effects of applying this technique over a lifetime. This book is both a memoir of one individual's evolutionary journey toward a conscious life and a practical guide for those interested in delving into the endlessly fascinating principles and applications of the Alexander Technique.
It’s a bit difficult for the beginner to read Alexander himself but to really understand his ideas, there’s noone better.
The Alexander Technique As I See It by Patrick Macdonald
If what follows can smooth the path of any pupil or teacher in the difficult and arduous task of clambering out of the pit that we have dug for ourselves and which has been, and is being dug for us, I shall be well satisfied. As, however, the ideas contained in the pages that follow arise from the truth of experience in learning and teaching this most important of techiniques, they can have universal application. It is open to any one to find the meanings contained therein. I would also like to say that I speak for myself. Different people interpret Alexander differently and I lay no claim to speak the only truth. - from the Preface
Body Awareness in Action: A Study of the Alexander Technique by Frank Pierce Jones
At one time or another almost everyone suffers from backache and physical tension. Because most of our complaints arise from our own unconscious bad habits, conventional treatment rarely brings more than temporary relief. F. M. Alexander maintained that because of the the influence of civilization we can no longer rely on our instincts. By continuing to rely on instinct instead of intelligence, man would no longer develop but degenerate: if we are to survive, our behavior has to be consciously determined. Alexander believed this to be the most important phase of man's development: the passage from subconsciousness to conscious control of body and mind. His technique, developed at the turn of the century, introduces conscious bodily control for physical reeducation.
In Body Awareness in action, Frank Pierce Jones presents the essential features of Alexander's method. Drawing on his long association with Alexander and his brother. Jones supplements Alexander's findings with his own carefully designed research at Tufts University Institute for Psychological Research. By measuring the differences between "habitual" and "teacher-guided" movement patterns, and by studying the actual mechanics of the body in achieving awareness. Jones provides scientific support for Alexander's ground-breaking discoveries. --- from book's back cover