for his palace
outside the city ... fanatic, identified as an Egyptian named Mohammed
Noureed ... old American submachine-gun ... two guards killed and a
third seriously wounded ... seized by infuriated mob and stoned to
death on the spot....

For a moment, he felt guilt, until he realized that nothing he could
have done could have altered the event. The death of Khalid ib'n
Hussein, and all the millions of other deaths that would follow it,
were fixed in the matrix of the space-time continuum. Including,
maybe, the death of an obscure professor of Modern History named
Edward Chalmers.

"At least, this'll be the end of that silly flap about what happened a
month ago in Modern Four. This is modern history, now; I can talk
about it without a lot of fools yelling their heads off."

She was staring at him wide-eyed. No doubt horrified at his
cold-blooded attitude toward what was really a shocking and senseless
crime.

"Yes, of course; the man's dead. So's Julius Caesar, but we've gotten
over being shocked at his murder."

He would have to talk about it in Modern History IV, he supposed;
explain why Khalid's death was necessary to the policies of the
Eastern Axis, and what the consequences would be. How it would hasten
the complete dissolution of the old U. N., already weakened by the
crisis over the Eastern demands for the demilitarization and
internationalization of the United States Lunar Base, and necessitate
the formation of the Terran Federation, and how it would lead,
eventually, to the Thirty Days' War. No, he couldn't talk about that;
that was on the wrong side of the knife-edge. Have to be careful about
the knife-edge; too easy to cut himself on it.

* * * * *

Nobody in Modern History IV was seated when he entered the room; they
were all crowded between the door and his desk. He stood blinking,
wondering why they were giving him an ovation, and why Kendrick and
Dacre were so abjectly apologetic. Great heavens, did it take the
murder of the greatest Moslem since Saladin to convince people that he
wasn't crazy?

Before the period was over, Whitburn's secretary entered with a note
in the college president's hand and over his signature; requesting
Chalmers to come to his office immediately and without delay. Just
like that; expected him to walk right out of his class. He was
protesting as he entered the president's office. Whitburn cut him off
short.

"Doctor Chalmers,"--W