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...
Price history
Oct 25, 2021
€9.54