L. Sprague de Camp

It does not pay a prophet to be too specific.

In writing a series of stories about the same characters, plan the whole series in advance in some detail, to avoid contradictions and inconsistencies.

There is no mistaking the dismay on the face of a writer who has just heard that his brain child is a deformed idiot.

The story of civilization is, in a sense, the story of engineering - that long and arduous struggle to make the forces of nature work for man's good.