Thomas Edison — "I don't think there's any substitute for a good idea."

"I am proud of the fact that I never invented weapons to kill."

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

"To invent, you need a good imagination and a pile of junk."

"I have a theory that the human voice is immortal. It is a form of energy that never dies. It just changes form. I believe that we can record the voices of the dead and play them back."

"Restlessness is discontent and discontent is the first necessity of progress. Show me a thoroughly satisfied man and I will show you a failure."