The other invader was on hands and knees, breathing in sips. Louis chopped at his neck, twice.

The invaders lay still in the lush yellow grass.

Louis Wu went to lock his door. At no time had the blissful smile left his face, and it did not change when he found his door fully locked and alarmed. He checked the door to the balcony: bolted and alarmed.

How in the world had they gotten in?

Bemused, he settled where he was, in lotus position, and did not move again for over an hour.

Presently a timer clicked and switched off the droud.

Current addiction is the youngest of mankind’s sins. At some time in their histories, most of the cultures of human space have seen the habit as a major scourge. It takes users from the labor market and leaves them to die of self-neglect.

Times change. Generations later, these same cultures usually see current addiction as a mixed blessing. Older sins — alcoholism and drug addiction and compulsive gambling — cannot compete. People who can be hooked by drugs are happier with the wire. They take longer to die, and they tend not to have children.

It costs almost nothing. An ecstasy peddler can raise the price of the operation, but for what? The user isn’t a wirehead until the wire has been embedded in the pleasure center of his brain. Then the peddler has no hold over him, for the user gets his kicks from house current.

And the joy comes pure, with no overtones and no hangover.

So that by Louis Wu’s time, those who could be enslaved by the wire or by any lesser means of self-destruction had been breeding themselves out of the human race for eight hundred years.