"The Power of Concentration" by Theron Q. Dumont

Free Kindle edition here.

• "Concentration makes the will and intellect act in unison."

• "Most people are imitators and copiers of their past selves."

• "It is just as easy to be courageous as cowardly. Courage concentrates the mental forces on the task at hand."

• "No one knows what they can do until they try."