Dowsing for Health and Harmony by Australian Spiritual Healer and Dowser, Chris Pisani.
It is in an easy to read format with step by step instructions on the many uses of both a pendulum and dowsing rods, including healing, balancing chakras, testing foods, and testing and removing geopathic stress as well as many others.
It can answer any questions you may have on the fundamentals, ethical and moral on the use of pendulums in healing, as well as any questions you may have regarding the use of dowsing rods.
An ideal book for both the experienced dowser and those wishing to learn the skill.