Once, in America, Swami Vivekananda was watching some boys. They were standing on a bridge trying to shoot at egg-shells that were floating on the river. The egg-shells bobbed up and down. The boys could not hit any of them. They fired the gun many times, but always missed the target!

They noticed that Swami Vivekananda was watching them. So they called out to him: 'Well, you are watching us. Do you think you can do better?'

Swami Vivekananda smiled and said: 'I will try.'

Then the boys said: 'It's not so easy as you think!'

Swami Vivekananda took the gun and aimed at the egg-shells. He stood very still for a few minutes. Then he fired the gun. He fired twelve times, and every time he hit an egg-shell! The boys were very surprised. How could any man shoot egg-shells like that? They thought. They said to Swami Vivekananda: 'Well, Mister, how did you do it? You must be a practised hand.'

Swami Vivekananda laughed and assured them he had never handled a gun before.

'Whatever you are doing,' he explained, 'the secret of success lies in the power of concentration. Put your whole mind on it. If you are shooting, your mind should be only on the target. Then you will never miss. If you are learning your lessons, think only of the lesson. In my country boys are taught to do this.'

The power of concentration is the only key to the treasure-house of knowledge.

--Swami Vivekananda