A colleague recently loaned this book to me and I enjoyed reading it. This is Reid's third book on "functional vocal training," and it seems to be a serviceable volume.
Reid's chapters cover the foundational points of vocal pedagogy -- muscles and movement, register, vowels, resonance, attack, and so on -- but they are not meant to be comprehensive instructional segments. Instead, Reid seems to use each chapter to clarify and expound upon his teaching techniques.
Some ideas here are new and provocative. For instance, Reid believes that poor breathing problems and breath control occur not as result of improper breathing habits or posture, but are a result of faulty vocal registration and coordination. By correcting the vocal coordination, one can usually form correct breathing technique.
Reid's ideas of the balance between teaching vocal techniques and emotional delivery are interesting and helpful, and it is clear that he is relying on some of the most modern discoveries about singing of the time (1974).
Though Voice: Psyche and Soma is better than many books out there about "proper" singing techniques, there are many superior books out there. Vocal Pedagogy by Clifton Ware, Discover Your Voice by Oren Brown, The Diagnosis and Correction of Vocal Faults by James McKinney, and The Structure of Singing by Richard Miller are all more modern, more comprehensive books on the instruction of singing. Voice teachers would get much more out of these books than Reid's.
In other words, if you are doing a doctoral dissertation on singing, this book deserves a look - otherwise, try other books first.