That is the great difficulty. By great struggle we get a certain power of concentration, the power of attachment of the mind to certain things. But then there is not the power of detachment. I would give half my life to take my mind off that object! I cannot. It is the power of co...ncentration and attachment as well as the power of detachment [that we must develop]. [If] the man [is] equally powerful in both — that man has attained manhood. You cannot make him miserable even if the whole universe tumbles about his ears. What books can teach you that? You may read any amount of books.... Crowd into the child fifty thousand words a moment, teach him all the theories and philosophies.... There is only one science that will teach him facts, and that is psychology.... And the work begins with control of the breath.
- Swami Vivekananda
(Delivered in San Francisco, March 28, 1900)The Complete Works of Swami Vivekananda/Volume 1/Lectures And Discourses/Breathing