Your Body Doesn’t Lie by John Diamond in mass market paperback. This book clearly explains energy/muscle testing, and is a great one for the basics to give to a skeptical mind. Short and sweet.
Infinite Mind by Valerie Hunt, 1996, hardback. One of the most scientific, yet mystical and personal accounts of the original research done on the human energy field, including the discovery of the vibratory rate of the aura.
The Promise of Energy Psychology by David Feinstein, Donna Eden, and Gary Craig. 2005. Paperback, very useful in understanding how to use Emotional Freedom Technique (EFT) and Energy Medicine together.
The Field by Lynn Mc Taggart, 2002, in paperback. A journalist’s report on the research and findings of those who are looking for an underlying universal field of consciousness and energy. Excellent.
Eastern Body, Western Mind by Anodea Judith, 1996, paperback. A huge work on the chakras, integrating several types of psychology with the development of the chakra system, way beyond the old color and musical scale and crystal material.
A Practical Guide to Vibrational Medicine by Richard Gerber, 2000, paperback. His update on the original work, and much better. He covers many of the types of energy medicine, does some explaining of theory and practice, and goes to great depth in his explanations.
Therapeutic Touch by Dolores Krieger, 1979, and all of her books. Very clear, very honest, very useful.
The Biology of Belief by Bruce Lipton, 2006 A maverick doctor discovers cellular communication. I think his CD set, The Wisdom of the Cells, is one of the best teachings on thought-field energy ever produced.