The over 12 lakh books in the university's libraries include tomes that are over 350 years old. The pages of many of the old books have become brittle and illegible with age, though they are in demand by researchers.

The contents of the books will be made legible using "sophisticated techniques" and preserved in the form of replicas as well as in the digital format.

"We have initially identified 47 rare and valuable books that need to be restored immediately. All the books were written between 1651 and 1857," said Calcutta University librarian Saumitra Sarkar.

According to him, about 25,000 books in the collection are "very old and rare and need to be restored".

The books will be "cleaned" and text and pictures will be retouched so that the contents can be preserved as duplicate books and digital data, added Sarkar.

The 47 books contain nearly 22,754 pages. The oldest among them are written in French and Latin and are consulted by linguists from India and abroad. There are also travelogues, history books and law books among the selection.

A large part of the Rs 1-crore fund released by the University Grants Commission to upgrade the CU libraries will be spent on the restoration of the first batch of books.

More than 1,200 people use the university libraries every day. The network is made up of the Central Library on the College Street campus, nearly 40 departmental libraries on seven campuses and two libraries of the Advanced Studies Centres.

An Online Public Access Catalogue provides access to the database of books, journals, theses, CDROMs and microfilms. The university also subscribes to nearly 4,000 electronic journals.