Signs and detours are part of daily life at the Countway Library as renovations proceed.

Amid pounding jackhammers and screaming saws, earplugged researchers are still quietly using Harvard's Countway Library of Medicine.

The Countway's $26 million renovation got under way in March 1998, but library staffers have another objective besides facilitating the work of contractors sprucing up and updating the place.

They have to stay in business.

"I think you can liken it to the ongoing responsibility of physicians to patients," said Paul Russell, John Homans Professor of Surgery and chairman of the Joint Library Committee, which oversees Countway's operations. "It was beyond the range of possibility to close the place. We had to rebuild it around ourselves."

Planning how to stay in business required having a lot of construction done at night, trying to minimize drilling in the nearby plaza to early morning, and -- oh yeah -- free earplugs.

''We went through three or four boxes of several hundred in three months,'' said Elizabeth Wu, the library's project manager for the renovations. ''We haven't gotten any irate customers.''

The symmetrical shape of the Countway Library's main staircase will be preserved, though renovations will extend it to another floor.

About 1,000 people a day use Countway's resources. With about 800,000 volumes stacked in its eight stories, Countway is one of the largest academic medical libraries in the country and is used by faculty, researchers, and students at the Harvard Medical School, Dental School and the School of Public Health. It is also used by people from other Harvard schools and by residents and staff from Harvard's affiliated hospitals. Countway reaches into cyberspace as well, with the library's page on the World Wide Web receiving per month an average of 225,000 "hits," or visits, from people seeking information via computer.

Though the building opened in 1965, Countway was created in 1960 with a formal agreement to merge the Boston Medical Library and the Harvard Medical School Library.

In recent years, just about everyone agreed that Countway should be renovated. More than three decades after it opened to accolades and an architectural award in 1965, the library was worn down. Elevators and heating systems were balky, the carpet worn, facilities for preserving rare books aging, and electrical wiring, crucial in the burgeoning information age, was at capacity.

"In 1965, we opened with just one photocopy machine. Only staff were allowed to use it. Electrical conduits were poured in the concrete floor. They're now stuffed full," said Countway Librarian Judy Messerle. ''The way libraries did business in 1965 is very different from how we do business now.''

Though they know how libraries did business then and do business now, the tricky part in designing the renovation was predicting how libraries -- Countway in particular -- will do business in the future.

''One of the things we struggled with most is the form libraries will take in the future,'' Russell said. ''Some people say that the library of the future will be the size of a desk.''

Despite increasing use of the Internet, recent surveys show that library usage is up, Messerle said. So Countway is planning to embrace the computer age.

Among the renovations will be increased wiring to all floors, to make future computerization possible, and a series of computer classrooms on the second floor. The classrooms will be equipped with modern projection equipment and powerful computers that can do molecular modeling and communicate with national databases.

''We're trying to get very close to the basic science,'' Messerle said. ''It's very challenging and very exciting to think about what the library of the future should be.''

Though the computer classrooms can make Countway a partner with teachers and their students, the traditional role of a library as a place to find information isn't being ignored.

One of the major changes in the renovation will be the addition of a reading room for medical and scientific journals. The researchers and doctors who use Countway are often very interested in articles about cutting-edge work done by colleagues around the world. That's why the journals are among the hottest items in the library, Messerle said.

A problem with their popularity, however, is that they often get taken to far corners of the library for a quiet read and are left there, making them unavailable when others need them. That will change in the renovated Countway.

The new reading room, to be located on the first floor where the administrative offices are now, will have all the latest journals, as well as computers so people can read journals on-line if the hard copies are being used. The reading room will be very comfortable, Messerle said, but the journals will have to be read there, ensuring they remain in the reading room for the next person to find.

Countway Librarian Judy Messerle (left) and Elizabeth Wu, renovation project manager, look over site plans.

''It'll be pretty spectacular,'' Messerle said. ''We think it'll be the most popular space in the whole building.''

The past hasn't been ignored in all this talk of the future. Countway's rare books collection, which is currently scattered among three floors of stacks, will be concentrated on the library's lower level. Temperature and humidity controls will be improved, ensuring that they'll be there for future generations of students and researchers.

The largest structural change at the renovated Countway will be a new staircase to the second floor. From the current entrance, visitors have the choice of a bank of elevators or two staircases down to the lower levels. One of the staircases down will be removed and changed into a staircase up.

That will increase access to the second floor, where a relaxed lounge and current reading material -- such as the day's newspapers -- will be located.

All this, unfortunately, can't be done without some disruption. The construction has been planned in kind of a domino fashion, with work on the library's lowest level and on the plaza slated to be completed first.

Once that level is secure and waterproof, the rare books will be moved in, freeing up space in the upper floors to shift books around and make room for construction there.

Last will be renovations to the first floor and L1, which is sandwiched between the first floor and the library's lowest level.

Through it all, Messerle asks for the patience and understanding of all involved.

''What we're trying to do here is position ourselves for the future in whatever form it will take,'' Messerle said. "It should make us incredibly modern when we come out at the other end.''