Freedom has many difficulties and democracy is not perfect, but we have never had to put up a wall to keep our people in.

Now is the time...for this nation to take a clearly leading role in space achievement, which in many ways may hold the key to our future on Earth.

The ancient Greek definition of happiness was the full use of your powers along lines of excellence.

Perhaps scientists have been the most international of all professions in their outlook... Every time you scientists make a major invention, we politicians have to invent a new institution to cope with it-and almost invariably, these days, it must be an international institution.

The world was not meant to be a prison in which man awaits his execution.

Our children and grandchildren are not merely statistics towards which we can be indifferent.

The courage of life is often a less dramatic spectacle than the courage of a final moment; but it is no less a magnificent mixture of triumph and tragedy.