Okay, I don't know exactly what the "subtle energy body" is. But here's what I'm interested in: learning to feel, activate, and balance first my internal energy system and then that of others. I'm not real interested in visualization techniques as I've found sensation-based techniques much more effective.   I've found a few books that address this in useful ways for me, and I'd like to know what books or media have helped others.   Here are three books that have particularly helped me.   Energy Work, by Robert Bruce. Bruce's Tactile Imaging method was amazing in teaching me to mentally activate acupoints and reflexology areas. Bruce's tactile imaging uses sense of touch, rather than visualization, to stimulate the flow of vital energy throughout the body. You learn how to wake up energy centers and move vital energy throughout the body. Bruce's easy-to-follow illustrations and exercises encourage safe, rapid results. (Bruce used to have his Tactile Imaging tutorial online, titled "NEW energy work", and you may be able to find it on wayback if you don't want to buy the whole book.)   Juice: Radical Taiji Energetics, by Scott Meredith. This book is a huge help in watching and moving the energy, finally offering a(n unusual!) framework that fits the way my practice has already been developing. It focuses on ways of paying attention to the energy, and what to look for, a different set of points to focus on (niwan, lingtai, dailing), and cultivating the energy paths. "Real taiji is about energy cultivation and deployment." He says it's about learning to feel and focus within yourself. "..the mechanism of true Taiji... functions to get your mind fully and pervasively interpenetrating your body exclusive of any blocking physical tension or muscularity so that spirit energy is connected seamlessly from feet to hands." We could say he trains you to feel the energy states and surges with in your tai ji practice with the goal of energy deployment in pushhands and beyond. Helped me connect even more with the energy coming up through my legs, and his descriptions of energy phenomena matched my own experience in many ways, which no other book has done.   Heavenly Streams: Meridian Theory in Nei Gong, by Damo Mitchell. I've only just finished reading this through the very first time. Mitchell gives a series of training exercises to develop the ability to feel and evaluate your meridians, along with the elementary Daoist theory necessary to determine which meridians you need to work on. Mitchell uses a sensation-based technique combining breath and intent, first to observe the activity on the meridian and then later, to activate it. He embeds the meridian work in an excellent and useful overview of Daoist theory, combined with many exercises and illustrations designed to develop the foundation skills needed to succeed in the advanced work.   These three books are all practice-based. Don't know that you'd get much just from reading them, but they might inspire you to get started!