Every minute, from inside and outside, promptings and temptations arise and accumulate in man. One cannot attend to all of them at the same time. So he fixes attention on the most important among them only. This is called concentration, avadhana. Concentration is needed to grasp any subject well. Purposefully directing the attention on a subject and fixing it there is called ekagrata, one-pointedness. This is also a condition of the mind. Concentration and one-pointedness help to focus our effort on any selected task. In fact, concentration is essential for all. It is the foundation of all successful endeavour. (DhyV, p. 15)