In a move to increase security at the Andover-Harvard Theological Library, all people entering the library on or after April 2 will be required to sign in at the guard's desk near the building's entrance, Charles S. Woodbury, circulation librarian at the library, said yesterday.

The increased security measures were prompted by the disclosure that several women students have found "threatening notes in block printing" in carrels at the library in recent weeks. Harvard police are presently investigating the threats.

Experimental

Library officials are instituting the new procedure on an experimental basis in order to obtain samples of the hand-writings of the people using the library, which is the main library of the Harvard Divinity School, Woodbury said, adding that library officials will compare the list of signatures to those on the threatening notes.

Guy V. Martin, dean of students at the Div School, said yesterday that to his knowledge no violent incidents have occurred at the library as a result of the notes. Martin added that he believes the library's security measure will make people more conscious of security at the Div School.

Peter W. Webster, a first-year Div School student and a guard at the library, said yesterday he thinks the new regulation is a good idea although it will create more work for library guards, who will be required to come to work half an hour earlier.

Webster said the reason the library does not currently require its users to present identification is that library officials wish to give ministers and students from other areas access to the library. At present, guards are only required to check books that people carry out of the building.

James A. Garrison, a Ph.D. candidate at the Div School, said yesterday he is not sure the measure will work. "In the final analysis, locks are for honest people. You can't legislate morality," Garrison said.