Few on the Harvard campus noticed it, but a quiet revolution has been evolving over the past past year.

The biological laboratories have played an active role in it. So have the Dining Services and the Criminal Justice Center. Even President Derek C. Bok, normally not known for his subversive tendencies, has taken part in the upheaval.

All have succumbed to the fax craze.

The first open signals came this fall, when the University released its new administrative telephone listings. Buried deep in the yellow pages was a previously unseen heading: "fax machines."

And now, at Harvard as in the rest of the U.S., fax machines have become the newest form of professional insignia. They perch on desks like pieces of art, symbols of academic prestige. They don't need to be used, just to be seen. Today, a fax is as important as the degree hanging on the wall above it.

The machines have revolutionized long-distance communication during the last decade, and fax sales have risen exponentially. Proposals, memos, documents, agreements can now be sent across the country or over seas in less time than it takes to dial the phone number.

The machines have become a standard, almost expected form of communication. And during the past year, the trend has hit Harvard with incredible speed.

According to Judy M. Matthews of the Office of Information Technology (OIT), Harvard bought--or "placed," as she likes to put it--a total of 68 fax machines during the last fiscal year. Another 30 have been bought since July 1, she says.

A grand total of 130 faxes are now in place on the Harvard campus, Matthews says. The University is stuffed with professors avidly faxing manuscripts to their New York publishers and scientists publicizing their latest research.

Some branches of the University seem to have taken the fax craze to extremes. The Government Department has not one, but four of the machines. And still the University keeps buying more.

"As more and more faxes are placed around the world, more fax machines are being used," said Linda Gillis, supervisor of the Message Center at OIT. "The fact is, more and more people are faxing."

The trend can often inspire wild flights of fantasy. One pictures the day when Bok, in his Massachusetts Hall office, and Dean of the Faculty A. Michael Spence, across the yard in University Hall, will communicate by fax. The two buildings are less than 500 feet apart, but each is equipped with its own fax machines. Like forts stocked for war, they are prepared to do administrative battle.

While this scenario might be a bit far-fetched today, it is not too far from the actual truth. Most of the secretaries who run the machines say the bulk of fax messages are sent within Harvard, from one department to another.

"It really saves walking," says a faxer at Phillips Brooks House Association. "We're totally dependent on it."

"It's a magic machine, like grace," says Joan Arnoff, a secretary in the Biochemistry Department.