Maturity is often more absurd than youth and very frequently is most unjust to youth.

The three great essentials to achieve anything worth while are: Hard work, Stick-to-itiveness, and Common sense.

I have a peculiar theory about radium, and I believe it is the correct one. I believe that there is some mysterious ray pervading the universe that is fluorescing to it. In other words, that all its energy is not self-constructed but that there is a mysterious something in the atmosphere that scientists have not found that is drawing out those infinitesimal atoms and distributing them forcefully and indestructibly.

There will one day spring from the brain of science a machine or force so fearful in its potentialities, so absolutely terrifying, that even man, the fighter, who will dare torture and death in order to inflict torture and death, will be appalled, and so abandon war forever.

It is the best book ever written on the subject. There is nothing like it!

The three things that are most essential to achievement are common sense, hard work and stick-to-it-iv-ness... Unfortunately, many of life's failures are experienced by people who did not realize how close they were to success when they gave up. I have far more respect for the person with a single idea who gets there than for the person with a thousand ideas who does nothing.

Nature is what we know. We do not know the gods of religions. And nature is not kind, or merciful, or loving. If God made me - the fabled God of the three qualities of which I spoke: mercy, kindness, love - He also made the fish I catch and eat. And where do His mercy, kindness, and love for that fish come in? No; nature made us - nature did it all - not the gods of the religions.