Merle Fainsod, professor of Government and director of the Russian Research Center, will become director of the Harvard University Library on July 1, it was announced yesterday. Fainsod succeeds Paul H. Buck in the post as Library head and also as Carl H. Pforzheimer University Professor.

At the same time, Douglas W. Bryant, currently associate director of the University Library, will assume the new position of University Librarian. A University Library Committee will also be created as part of a major restructuring of the Library's top administration.

Bryant will be responsible for day-to-day management of the 7 million volume library, the third largest in the U.S., while Fainsod will deal with major questions of policy. Bryant will also take charge of directing the Harvard College Library, which includes Widener, Lamont, Houghton, and the Fine Arts Library, or about one-half the entire University collection. Previously supervision of the College Library has been under the aegis of the director.

The new University Library Committee, which will be chaired by Fainsod, will include representatives of the major libraries of the University. At present no University-wide body exists to bring together the 93 units in the Harvard Library system.

The changes toward greater centralization of the library system follow the trend established under Buck's administration. As part of this effort, four official "interlocking" committees have been set up in the past few years to coordinate among the different branches such aspects of library management, as cataloguing and installation of mechanical devices.

Fainsod says he does not foresee any major policy shifts when he takes over. "It is an excellent library, and I will try to keep it that way," he stated yesterday. Fainsod added that he expects to spend his first year primarily in familiarizing himself with the Library's operation.

In addition to his new duties, Fainsod, who is 57, will maintain his present teaching schedule.