"I was bored stiff," said Louis Wu. "'Tell us about your last sabbatical, Louis.' 'But how can you stand to be that much alone, Louis? How clever of you to invite the Trinoc ambassador, Louis! Long time no see, Louis.' 'Hey, Louis, why does it take three Jinxians to paint a skyscraper?'"

"Why does what?"

"The Jinxians."

"Oh. It takes one to hold the paint sprayer, and two to shake the skyscraper up and down. I heard that one in kindergarten. All the dead wood of my life, all the old jokes, all in one huge house. I couldn't take it."

"You are a restless man, Louis Wu. Your sabbaticals — it was you who originated the custom, was it not?"

"I don't remember where it started. It caught on pretty well. Most of my friends do it now."

"But not as often as you. Every forty years or thereabouts, you tire of human companionship. Then you leave the worlds of men and strike for the edge of known space. You remain outside known space, all alone in a singleship, until your need for company reasserts itself. You returned from your last sabbatical, your fourth, twenty years ago.

"You are restless, Louis Wu. On each of the worlds of human space, you have lived enough years to be known as a native. Tonight you left your own birthday party. Are you becoming restless again?"

"That would be my problem, wouldn't it?"

"Yes. My problem is one of recruiting only. Yon would be a good choice as a member of my exploration team. You take risks, but you calculate them first. You are not afraid to be alone with yourself. You are cautious enough and clever enough to be still alive after two hundred years. Because you have not neglected your medical needs, your physique is that of a man of twenty. Lastly, and most important, you seem actually to enjoy the company of aliens."

"Sure." Louis knew a few xenophobes, and regarded them as dolts. Life got awfully boring with only humans to talk to.