Recently I came across some popular non-fictions in the spiritual tradition (published in USA) on the subject of OBE: out-of-body experience. An out-of-body experience is an experience that typically involves a sensation of floating outside of one's body and, in some cases, perceiving one's physical body from a place outside one's body. Physical or mental trauma can induce an involuntary OBE. Deep meditation can lead to OBE, and so can many methods induce such an experience.
In the past, both in the East and the West, induced OBE had been considered secret practices. And Buddhist and Taoist traditions in China carefully distanced themselves from "OBE with a personal agenda". I believe for two reasons: firstly, it is in direct opposition to their religious beliefs, and secondly, lest their religions might be persecuted by the authority (though sometimes they were still persecuted despite their distancing from OBE with a personal objective, but that will be another story) In China's mainstream religious tradition, those who practiced any form of OBE for personal gains were unfortunately oftentimes being considered as "evil cultists" (邪魔外道). If we do not assume that the authority was always on the right side (politically or morally), then we shouldn't assume that all "evil cultists" who practiced OBE with personal ambitions were necessarily the bad guys! In Chinese history, Master Hung and his disciples who organized the Taiping Revolution had the "noble goal" of overthrowing foreign invasion is an example worth some serious thoughts by contemporary kind heart humanists. Unfortunately Hung's army failed in their venture, and their position in Chinese history has therefore been debatable and being debated till now.
In Dynasty China, those who practiced fortune telling or Feng Shui oftentimes were being considered to have special spiritual powers (though they [wisely] usually refrained from involving into politics), and I contend that some of these people did believe they had such power through their practice of OBE! Such techniques were oftentimes passed on only through an oral tradition for obvious reason of personal security. A contemporary popular author and practitioner who studied it a lot and wrote a lot on the subject is a Japanese: 高騰聰一郎, many of his books has been translated into Chinese (published in Taiwan). Nowadays, this oral tradition is more prevalent in Taiwan, due to the fact that Hong Kong people are more suspicious of superstitious beliefs, and the mainland is not a place too kindly to religious/spiritual/mythical orders not directly under the Government monitored religions, notably the closely monitored big four: Taoism, Buddhism, Christianity and Islamism.
In the West OBE has become part of popular culture with many popular non-fictions exposing different ways to induce one into different OBE zones. In our contemporary western culture, mysticism and mystical practice like self-induced OBE have become a subject of personal interest. In the modern utilitarian culture, everything will be fine as long as firstly it is not against the law, and secondly it is good for you for whatever reason! A society of spiritual supermarket (and infidelity is not a problem except for the orthodox societies which a modern man will frown upon and consider a "dying industry" anyway). All living great masters of any profound teaching, like it or not, it is now the buyer's market! All eager learners, like it or not, learn anything at your own risks!