I owe my success to the fact that I never had a clock in my workroom.

The first requisite for success is to develop the ability to focus.

My success is due more to my ability to work continuously on one thing without stopping than to any other single quality.

The secret of success is focus of purpose.

The barrier to success is not something which exists in the real world; it is composed purely and simply of doubts about ability.

The first requisite of success is the ability to apply your physical and mental energies to one problem without growing weary.