This is an excerpt from Cave In The Snow by Vicki Mackenzie (the book she wrote about renowned Buddhist nun, Tenzin Palmo: the first Western woman to ascend the hierarchy of Buddhist tradition and practice in the East), lent to me by my beloved.
"When she was not doing her preliminary practices she worked on her Single Pointed Concentration - the meditative discipline which trains the mind to focus single-pointedly on one subject without interruption. Yogis were said to be able to stay in this state for days, weeks, months even, without moving, their mind totally absorbed on the wonders of their inner reality. Single Pointed Concentration, or Samadhi, was essential for penetrating the nature of reality and discovering absolute truth. It is also exceedingly difficult, the mind habitually wanting to dance all over the place flitting from one random thought to another, from fantasy to fantasy, perpetually chattering away to itself, expending vast quantities of energy in an endless stream of trivia. The mind was like a wild horse, they said, that needed to be reined in and trained. When the mind's energy was harnessed and channelled like a laser beam on a single subject, its power was said to be tremendous. Ultimately that was the high-voltage power-tool needed to dig down into the farthest reaches of the mind, unlocking the greatest treasures buried there."