Pittsburgh is a leading candidate to land a library and institute now located at the Massachusetts Institute of Technology that would bring to this city one of the nation's pre-eminent collections on the history of science and technology.

The 50,000 rare books, 30,000 secondary titles and assorted other materials include one of the world's three greatest assemblages of works by and about Sir Isaac Newton. They are contained in the Burndy Library, which is weighing a move to another city now that an agreement that has kept it on MIT's Cambridge, Mass., campus since 1992 will end in August 2007.

The Burndy and an affiliated research institute need two years to plan their relocation.

Pittsburgh has emerged as a possible new home, partly because of academic and library programs available at the University of Pittsburgh and neighboring Carnegie Mellon University. Other sites being considered are Johns Hopkins University in Baltimore, Indiana University in Bloomington, Ind., and a consortium of universities in Philadelphia.

Affiliated with the Burndy is the Dibner Institute for the History of Science and Technology, an international center for advanced scientific research. It sponsors graduate fellowships and hosts symposiums and other gatherings open to scholars worldwide.

The two Pittsburgh campuses, led by Pitt, are preparing a joint proposal, spurred not only by the collection but also by the Dibner Institute's potential as a magnet for scholars working in fields for which Pittsburgh has become known.

"We are already the No. 1 place in the world for the philosophy of science," said Pitt Provost James Maher. "We are one of the very leading places in the world on the history of science and technology.

"This would bring history of technology in Pittsburgh up to a prominence that we already occupy in philosophy of science. That would be quite a prestigious thing for both universities," he said.

Maher said discussions were very preliminary, adding, "I can't say a lot."

Campuses competing to host the library and institute will be evaluated on various factors such as quality and vibrancy of programs, commitment to supporting and finding adequate space for the institutions, and the manner in which they will be integrated into campus offerings

The Burndy Library was established in 1941 to accommodate holdings of the late Bern Dibner, a wealthy Ukrainian-born engineer, author and philanthropist whose fascination with Leonardo da Vinci spurred him to become an avid collector. The various items Dibner amassed, including manuscripts and artifacts like early microscopes, are rivaled by only a couple of other collections in the United States, said Ronald Brashear head of special collections at the Smithsonian Libraries, part of the Smithsonian Institution in Washington, D.C.

To mark America's bicentennial, Dibner donated a quarter of the Burndy's holdings in 1974 to the Smithsonian, which maintains a library in his name, Brashear said. The rest of the Burndy, then located in Norwalk, Conn., later moved to MIT.

"There aren't that many collections, not that size and scale that cover the wide breadth and also have a research component," said Brashear, who also is curator of the Smithsonian's Dibner Library of the History of Science and Technology.

Across the nation, hundreds of special collections kept in various academic and library settings chronicle topics from medicine to children's literature to golf. They can be noteworthy by their size, significance of holdings or both. Often, as was the case with Dibner, they are the legacy of someone whose wealth and personal curiosity on a subject mushroomed into a major resource for scholars in that field.

Around 1930, Dibner purchased a book about the history of invention and became fascinated by da Vinci, according to the Dibner Institute's Web site. Before too long, Dibner was acquiring rare books and other items not only on da Vinci but also on the Renaissance and other aspects of science and technology dating from the 15th century to modern time.

Dibner, who founded the Burndy Engineering Co. in 1924, had contacts with dealers and auction houses in New York, Philadelphia, London, Paris and Florence, Italy, said Philip N. Cronenwett, Burndy Library director.

"Instead of going out and becoming a playboy, what he did was go out and become a historian of science," Cronenwett said. "He had a consuming passion, and it was to be absolutely certain that, in the future, people knew what the history of science and technology was all about."

Dibner himself wrote more than 100 books and articles on various scientific subjects, including installation of the first trans-Atlantic telegraph cable.

The Burndy's holdings include the Grace K. Babson Collection, described as one of the world's three great gatherings of work by and about Sir Isaac Newton, a 17th-century mathematician and revolutionary science figure. The Burndy and the Dibner Institute are housed in the Dibner building at MIT and are supported by The Dibner Fund of Wilton, Conn., which has $74 million in assets.

Those involved in talks between MIT and the Dibner Institute have not disclosed reasons for the 12-year agreement's termination. Patti Richards, a spokeswoman at MIT, confirmed that the institute and library were exploring other locations, but she had no further comment. A call to the institute was not returned.

Cronenwett said that in his view, the arrangement is ending because of a "lack of interest that we showed toward MIT and the lack of interest that MIT showed toward us."

"It didn't click," he said.

The Burndy collection is seen as a potential fit with both Pitt's History and Philosophy of Science department and the school's Center for Philosophy of Science. Carnegie Mellon's tech-heavy campus is a draw too, in part because of an existing focus in the history of technology and holdings within the Hunt Institute, devoted to the history of botany and various areas of plant science, those privy to the discussions said.

N. John Cooper, dean of the school of arts and sciences at Pitt, said the Burndy Library and Dibner Institute would help enrich the undergraduate and graduate programs at both universities. Carnegie Mellon Provost Mark Kamlet said his campus, too, is hopeful that Pittsburgh will be selected.

"We would be delighted," Kamlet said. "It would be a nice feather in our region's cap."