This is the cognomen adopted by Terence Gray, an Irish aristocrat who started publishing a series of mystifying books about mysticism during the 50's and 60's, which along with those of Reps and Alan Watts were Western takes on Zen. Meaning action of non-action, a Taoist concept, Gray writes about the paradoxical explanations of such teachers as Hui Neng, Ramana Maharshi, Padma Sambhava and Huang Po. He especially elaborates what I consider the extreme stance of Shen Hui, who insisted that since enlightenment is sudden, there is no method or way to "practice" attaining it. There is a nice paper by Hoyu Ishida on this, which takes Shen Hui to task for proposing that since humans are already enlightened there is no need for practice, i.e. meditation. While other teachers have advocated the former proposition, they reject the latter. Without the formal discipline of sitting meditation practice, realization of one's innate buddha nature will never happen, because the mind is too chaotic, not to mention seductive in assuring us all is well and good as long as we think we are already enlightened.
Wei Wu Wei does offer many good down to earth explanations of obscure Eastern doctrines, such as anatta, or non-self. He says for example: "We do not possess an 'ego'. We are possessed by the idea of one." There are a few examples quoted here at a website devoted to his teachings.