Millions of books are disappearing from college and university libraries all over the country, including here in Pittsburgh.

Disappearing may not be the right word, for the books have not been stolen or lost. The books have purposely been earmarked for transport and transfer to not-so-distant storage facilities.

The books have been moved to make way for many things, including computers and study areas where talking, collaboration and spirited discussion are not only permitted but encouraged.

The transformation has been spurred by the Internet, which is changing the way college and university students use their libraries.

Rush Miller, director of the University of Pittsburgh Library System, said "50 to 60 percent of students make heavy use of the library without coming through the front door."

He said students are spending slightly less time in libraries, with a downward trend continuing at a "very slow pace."

Dr. Miller said 600,000 to 700,000 books per year are checked out of Pitt libraries, and seven to 10 million retrievals of materials are made on computers.

That's because of the growth of digital libraries.

Print journals and scholarly articles are increasingly available online. And while campus libraries are still buying journals in print, Pitt has 60,000 scholarly journals online.

What the Chronicle of Higher Education called the nation's first mainly digital library opened in 1994 at the University of Southern California.

That university set a scenario that has been played out at schools across the country.

At the time, the library system's director, Lynn O'Leary-Archer, told the Chronicle that the university "moved thousands of books into a storage center a few blocks from the campus to make rooms for 250 computers, communal work areas and rooms where students can work on multimedia projects."

She continued, "Campus libraries have become places where people can exchange ideas and study over a cup of coffee. There's no stereotypical librarian in a bun and sensible shoes telling people to be quiet."

Since Carnegie Mellon University built a book depository four years ago, more than 200,000 library books have been moved into it.

"We are getting ready to build an addition onto the depository because it's almost full," said Gloriana St. Clair, dean of university libraries.

CMU has four libraries, 1,084,013 books and 26,694 subscriptions to journals and periodicals.

"We have not received complaints about books moving into storage," Dr. St. Clair said. "In fact, the students like it. They are very favorable toward electronic information. They are heavy users of the Web and electronic resources. Sometimes they say move more books into storage."

Stored books can be retrieved within a day by CMU students who need them.

Although CMU still subscribes to journals, many have become available on campus only in the electronic form in the past five years.

In recent years, Pitt has moved about 1.3 million books -- about 20 percent of its books -- into a Point Breeze storage facility, Dr. Miller said.

Books in storage can be retrieved in less than a day for anyone who needs to use them. The storage facility has room for 3 million books, which she said is a good thing because all 20 campus libraries are overcrowded.

The growth of digital libraries is helping solve one of the age-old dilemmas faced by students who cannot read books or journals needed for a paper or research project because someone else has it. "We've done studies, and some items just perennially get lost," Dr. Miller said.

In those cases, the library looks for online versions so that every student has access.

Since the mid 1990s, Dr. Miller said there have been "huge transformations" in libraries.

"Thirty-three years ago my focus was on books, and how to get enough money for more books, and you never had enough" money or books, she said.

Pitt now has more than 250,000 electronic books accessible on a computer from anywhere.

Dr. Miller said more books are becoming available online, especially those published before 1920, which are not subject to copyrights.

The professionals who run libraries are well aware that the times are changing, and they work -- and network -- to try to stay on top of needs and trends and to find ways to entice students to physically enter library buildings.

About seven years ago, Pitt surveys indicated that students thought the libraries were "physically uninviting."

Interiors were repainted and new carpets were installed.

"We have worked very hard to make every library on campus more inviting and friendly," she said.

She said there are "multiple cultures" in different libraries, including elegant reading rooms, quiet study rooms and "noisier rooms" where students can interact.

"Everything we have done has been based on feedback from students," Dr. Miller said.

Campus libraries are not your grandparents' style of library.

Coffee bars and snack shops are showing up in campus libraries all over the country, and they've proved to be wildly popular. Carnegie Mellon has the Maggie Murph Cafe -- named after Andrew Carnegie's mother -- in the Hunt Library. Pitt's Hillman Library, used mainly by undergraduate students, has a coffee shop, whimsically named The Cup and Chaucer.

"They love it," Dr. Miller said. Then Pitt went a step farther and allowed drinks and snacks to be taken into the stacks and study areas.

"When someone checks a book out of the library and takes it home, they are probably eating and drinking over it. We have not had a single book damaged" since this change went into effect, she said.

"A lot of the old library rules were probably good in the day, but it was overly cautious," Dr. Miller said. After food and drink were permitted, she said, "we found more people wanting to come to the library."

University and college librarians are continually looking for ways to serve ever-increasing amounts of information to their "customers."

Carnegie Mellon, Penn State and the University of Pennsylvania are among the members of the Digital Library Federation, which was founded in 1994. Librarians meet, in person and online, to discuss changes and trends.

"Books do not seem to be going away and books continue to be produced," Dr. St. Clair said.

"Book publishing is a flourishing business, but there is a transition in books toward electronic production," said Dr. Miller. "Will we still have books in the future? I don't have the answer to that.

"Libraries did not invent books. Our job is to organize information in what ever format is available."