Women will forgive anything. Otherwise, the race would have died out long ago.

Peace is an extension of war by political means. Plenty of elbow-room is pleasanter -- and much safer.

A "critic" is a man who creates nothing.

I was there to see beautiful naked women. So was everybody else. It's a common failing.

Once you get to earth orbit, you're halfway to anywhere in the solar system.

Heinlein's Rules for Writers Rule One: You Must Write Rule Two: Finish What Your Start Rule Three: You Must Refrain From Rewriting, Except to Editorial Order Rule Four: You Must Put Your Story on the Market Rule Five: You Must Keep it on the Market until it has Sold

His older self had taught his younger self a language which the older self knew because the younger self, after being taught, grew up to be the older self and was, therefore, capable of teaching.