Question: Master Chinmoy, what do you mean by "concentration"?

Sri Chinmoy: Concentration is the open secret of focusing all one's attention on a particular object or person in order to enter into and have one's identification with that object or person. The final stage of concentration is to discover and reveal the hidden ultimate truth in the object of concentration. What concentration can do in our day-to-day life is unimaginable. It most easily separates our heart's Heaven from our mind's Hell so that we can live in the constant delight and joy of Heaven and not in the perpetual worries, anxieties and tortures of Hell while we are here on earth.
Sri Chinmoy, AUM — Vol. 3, No.11,12, June — 27 July 1968, Aum Centre Press -- Santurce, P.R., 1968