Fear of Life
In my view, this is Lowen's most important theoretical work. Even though he has written prolifically elsewhere on the many aspects of his mind-body modality, Bioenergetics, toward the end of this book he brilliantly and definitively delineates key distinctions between Freud and Reich, as he discusses the former's limitations and the latter's breakthrough contribution to the history of human self-awareness. He also provides brave and open-minded readers with a specific bodywork exercise by which they may test out his theories for themselves.
Anyone who wants to pursue this further and attain a better understanding of bioenergetic grounding can check out this book as well: http://www.amazon.com/Pleasure-Alexander-Lowen/dp/0974373729/ref=sr_1_1?s=books&ie=UTF8&qid=1323360085&sr=1-1
Finally, once you feel that you have a sufficiently solid theoretical grasp of grounding, I strongly suggest you grab one of these: http://www.technologychangesmorality.com/content/way-vibrant-health, with this caveat: bodywork exercise is not to be entered into lightly, and while solid mentorship for beginners is often very important, it is also, unfortunately, difficult to find. So enthusiasts who for whatever reasons choose to pursue the work more or less on their own should strive to keep a healthy balance between curiosity and adventure on one hand, and common sense on the other.