The first requisite for success is the ability to apply your physical and mental energies to one problem incessantly without growing weary.
I haven't failed, I've found 10,000 ways that don't work.
There's a way to do it better...find it.
The best thinking has been done in solitude. The worst has been done in turmoil.
The doctor of the future will give no medicine, but will interest his patients in the care of the human frame, in diet, and in the cause and prevention of disease.
Show me a thoroughly satisfied man, and I will show you a failure.
Restlessness and discontent are the necessities of progress.
Opportunity is missed by most people because it is dressed in overalls and looks like work.
Nearly every man who develops an idea works it up to the point where it looks impossible, and then he gets discouraged. That's not the place to become discouraged.
Time is really the only capital that any human being has, and the only thing he can't afford to lose.
Ignorance is the night of the mind, but a night without moon or star.