A. Ronald Holt - The Yoga from Yuggoth
Among the abilities necessary for the performance of successful ritual magic are two which are infrequent: mental, concentration, and vivid visualization. In light of this fact it would seem that more magicians would actively seek to develop these abilities in themselves than do. Why they do not is a mixture of three reasons: human intertia (i.e. it's hard work), a philosophical distaste for techniques by meditative Eastern religions.