Thomas A. Edison

Anything that won't sell, I don't want to invent. Its sale is proof of utility, and utility is success.  

Be courageous. I have seen many depressions in business. Always America has emerged from these stronger and more prosperous. Be brave as your fathers before you. Have faith! Go forward! 

Being busy does not always mean real work. The object of all work is production or accomplishment and to either of these ends there must be forethought, system, planning, intelligence, and honest purpose, as well as perspiration. Seeming to do is not doing. 

Discontent is the first necessity of progress. 

Everything comes to him who hustles while he waits. 

Genius is one percent inspiration and ninety-nine percent perspiration. 

Great ideas originate in the muscles. 

Hell, there are no rules here - we're trying to accomplish something. 

His genius he was quite content in one brief sentence to define; Of inspiration one percent, of perspiration, ninety nine. 

I have not failed. I've just found 10,000 ways that won't work. 

I know this world is ruled by infinite intelligence. Everything that surrounds us- everything that exists - proves that there are infinite laws behind it. There can be no denying this fact. It is mathematical in its precision. 

I never did a day's work in my life. It was all fun. 

I never did anything by accident, nor did any of my inventions come by accident; they came by work. 

I start where the last man left off. 

If we did all the things we are capable of, we would literally astound ourselves.