The human bank clerks and accountants who did what was still called “bookkeeping” had very seldom bothered to write in the “19” before the two digits they had entered. These were taken for granted; it was a matter of common sense. And common sense, unfortunately, was what computers so conspicuously lacked. Come the first dawn of ’00, myriads of electronic morons would say to themselves ’00 is smaller than 99. Therefore today is earlier than yesterday—by exactly 99 years. Recalculate all mortgages, overdrafts, interest-bearing accounts on this basis…” The results would be international chaos on a scale never witnessed before; it would eclipse all earlier achievements of artificial stupidity—even Black Monday, 5 June 1995, when a faulty chip in Zurich had set the bank rate at 150 percent instead of 15 percent.

There were not enough programmers in the world to check all the billions of financial statements that existed, and to add the magic “19” prefix wherever necessary. The only solution was to design special software that could perform the task, by being injected—like a benign virus—into all the programs involved.

During the closing years of the century, most of the world’s star-class programmers were engaged in the race to develop a “Vaccine ’99”; it had become a kind of Holy Grail. Several faulty versions were issued as early as 1997—and wiped out any purchasers who hastened to test them before making adequate backups. The lawyers did very well out of the ensuing suits and countersuits.

Edith Craig belonged to the small pantheon of famous women programmers that began with Byron’s tragic daughter Ada, Lady Lovelace, continued through Rear Admiral Grace Hopper, and culminated with Dr. Susan Calvin. With the help of only a dozen assistants and one SuperCray, she had designed the quarter million lines of code of the DOUBLEZERO program that would prepare any well-organized financial system to face the twenty-first century. It could even deal with badly organized ones, inserting the computer equivalent of red flags at danger points where human intervention might still be necessary.