You might think this craze is a variation of the self-help spectrum, or a variation of the religious concept of prayer, or a sad form of the most primitive magical thinking... but to the practitioners of Manifestation, or the Law of Attraction, it is a technique for "manipulating the energy and life-force of the universe," to cause the things you want or need to appear magically in your life. Perhaps old age has made me a cynic, but I do feel that during my lifetime, popular beliefs have become steadily more basically stupid. But huge amounts of $$$ are being made with this scam, by selling books or creating how-to websites. The idea has been shamelessly promoted on television and most other media.

Wikipedia traces the basic idea back to the so-called New Thought movement, when early in the 19th Century a certain Phineas Quimby introduced a form of health quackery which aimed to cure disease by exposure of the patient to a vigorous pep-talk by Quimby... "Your disease is ALL IN YOUR MIND... realize that, and you will be cured!" Quimby had been experimenting with curing disease using hypnotism/Mesmerism, and decided one day to try to eliminate the hypnosis ritual and just keep the pep talk he had been delivering to the patient "in a trance."  Andrew Jackson Davis, the Spiritualist forerunner of prophet and quack healer Edgar Cayce, introduced the concept of a mystical "Law of Attraction," but it was eventually again a member of the continually expanding "New Thought" movement, Prentice Mulford, along with fellow believers, who removed the specific health limitation/application and advocated the technique as a way of getting anything whatsoever that you think you need. The New Thought movement was basically religious, attempting to synthesize the teachings of all the world's religions into a single doctrine. But as the basic idea of just stating out loud what you need, and keeping those needs in mind, was stripped out of the New Thought overcoat, the technique no longer needed gods, and became a supernatural power possessed by the human mind, which needed only to be developed by training! Three of the most popular self-help books in the era 1940 - 1985 were based on this concept, the "Power of Positive Thinking." As usual in pseudoscience, the already pretty primitive idea has been dumbed down even further over the past 20 years, repackaged and successfully resold, as "Manifesting." The evolution of this idea closely tracks that of Mindfulness. Like Mindfulness, Manifesting has its entire origin within a religious movement, but in order to package it for mass consumption, all religious elements are eliminated and replaced by pseudoscientific vagueness. "Let the universe know clearly what you want, by following this simple ritual!" And plenty of different books and websites offer plenty of totally different rituals (and props, such as "magic crystal" gemstones, or special candles) that you absolutely have to do before your needs and desires will become known to "the universe," which will then immediately supply them!  Of course as we have already emphasized, the very essence of magical thinking is that "wishing makes it so!"  If you want it really really hard (but just how hard is that?) you will get it... maybe, someday, kind of, sort of, in a manner of speaking.