Dumont, T: Power of Concentration

The Power of Concentration is a top self-help book on the subject of concentration by Theron Q. Dumont that contains this excerpt:

It is of the utmost value to learn how to concentrate. To make the greatest success of anything you must be able to concentrate your entire thought upon the idea you are working on. The person that is able to concentrate utilizes all constructive thoughts and shuts out all destructive ones. The greatest man would accomplish nothing if he lacked concentration. It is of the utmost value to learn how to concentrate. To make the greatest success of anything you must be able to concentrate your entire thought upon the idea you are working on. The person that is able to concentrate utilizes all constructive thoughts and shuts out all destructive ones. The greatest man would accomplish nothing if he lacked concentration.
We all know that in order to accomplish a certain thing we must concentrate. It is of the utmost value to learn how to concentrate. To make a success of anything you must be able to concentrate your entire thought upon the idea you are working out.
Do not become discouraged, if you are unable to hold your thought on the subject very long at first. There are very few that can. It seems a peculiar fact that it is easier to concentrate on something that is not good for us, than on something that is beneficial. This tendency is overcome when we learn to concentrate consciously.