The Order I'm currently reading Daniel Reid's 'Harnessing the Power of the Universe'. It is the most comprehensive book I've found on the history of qigong development in China as well as giving great detail on the various types of energy within us and around us. An excellent book.
Here's a tasty excerpt:
"In human life, most people enslave their minds and spend their energies to serve their bodies and satisfy their desires, thereby 'mistaking the servant for the master'. In the higher orders of the universe, which human life was designed to reflect, spirit is the master, and energy is the tool through which the spirit expresses itself creatively in material form. In order to harness the power of the universe for the benefit of humanity, human beings must pattern their bodies as well as their minds on the universal order of creation reflected in nature and the cosmos and known as the Tao, for this is the context in which human life evolved. When practising the Tao, one must learn to balance physical health and vitality with spiritual awareness and virtue, for that is the one and only way the Tao works."  ¶ 12:09 p.m.