Paul H. Buck, Pulitzer Prize-winning historian and dean of the Faculty from 1942 to 1953, died suddenly at his home in Cambridge on December 23. Buck, who had been in failing health, was 79 years old.

His career at Harvard as a professor, dean, provost and director of the University library spanned 50 years and established Buck as a leading author and administrator.

Buck received the Pulitzer Prize in 1938 for "The Road to Reunion," considered "the standard book" on reconstruction after the Civil War, Donald H. Fleming, Trumbull Professor of American History, said yesterday.

Buck's study, an "innovative, imaginative work," concentrates on the re-establishment of ties between the North and South, rather than treating the period of reconstruction as "a tragic era," Frank B. Friedel, Warren Professor of American History, said yesterday.

During the years 1945 to 1953, while President James B. Conant '14 spent much time in government service, Buck ran the University in his capacity as provost and dean.

Regarded as "a man who was sensitive, responsive to faculty." Buck put the General Education program into effect, began the integration of Harvard and Radcliffe, and strengthened the House system, Freidel said.

Buck also established programs for computer research, social relations, engineering, applied physics and Russian studies.

During the McCarthy era, Buck demonstrated "qualities of statesmanship" in his defense of Harvard's academic freedom from Congressional attacks which he believed infringed upon the University's constitutional rights, John van Vleck, Hollis Professor of Mathematics and Natural Philosophy Emeritus, and a friend of Buck's for a half-century, said yesterday.

As director of Widener Library from 1955 to 1964, Buck improved its administrative efficiency, increased its size by 1.4 million volumes, and initiated 14 new projects, including plans for the establishment of the John F. Kennedy Presidential Library.

Buck's lasting contribution to library science was his emphasis on the importance of libraries to teaching and research. Edwin E. Williams, associate University librarian, said yesterday.

Buck is survived by his wife, Sally Betts Buck, and two sisters, both living in California