What Is Concentration?
An uninterrupted continuation of the flow of thought and undivided attention is concentration. It is the result of a well-regulated and controlled thought process. It is accomplished by patient and persistent effort. It is a reward of the highest value. There is no real effort connected with it, but you become so engrossed and interested in your thought that you are conscious of nothing else. Everything else is excluded and your whole consciousness is concentered upon one thought.
One moment's complete concentration will go farther toward the mastery of a lesson or solution of your problem than much time spent in idle, disconnected thought.
This is a faculty not easily mastered, but when once harnessed and under your control has the greatest constructive power.