He died at his home in Berkeley from natural causes.

"James Kettner was a wonderful colleague and a warm and loving human being," said Jon Gjerde, chair of the Department of History. "He was a devoted teacher, a learned scholar, and a dedicated servant to his campus and department. Most of all, he was a friend whose gentle kindness was apparent to everyone he touched. Jim will be sorely missed by all those who knew him at Berkeley and elsewhere."

Kettner was born on Oct. 4, 1944, in Greenville, Ohio. After receiving a bachelor's degree from Harvard University in 1966, he was awarded a Marshall Scholarship from the British government and attended the University of Sussex in England, obtaining a second bachelor's degree in history.

He received his Ph.D. in history from Harvard. His doctoral thesis, "The Development of American Citizenship 1608-1870," was the 1975 winner of the Jamestown Prize. The prize, awarded by the Institute of Early American History and Culture in Williamsburg, Va., is considered a great honor by academics in his field.

"He was proud that the doctoral thesis book won the Jamestown Prize and was quoted in a Supreme Court case," said Kettner's sister, Pamela Engel. "But I think he was probably the most proud of his teaching and his students."

Kettner came to UC Berkeley as a lecturer in 1973 and worked his way up to professor. He taught undergraduate and graduate students and welcomed the opportunity to advise them.

"He was graduate advisor probably for 15 years and kept his door open all day long," said UC Berkeley history professor Robert Middlekauff, Kettner's longtime friend and colleague. "His office hours were from about 6:30 in the morning until he went home at night. He really believed in the study of history, and he just believed powerfully in education, and he was genuinely fond of students and wanted to help them.

"Jim was universally admired because he worked so hard and was willing to do anything to help students in the department. He was somebody who just gave freely of himself to the department, and his colleagues recognized that."

Kettner spent his career at UC Berkeley teaching, serving for several years as vice chair of graduate studies in the history department, participating on departmental committees, and serving for numerous years as acting chair of the department during the summer. Friends and colleagues described him as a selfless, warm, thoughtful and quiet man who helped shaped the successful careers of many graduate students.

Kettner is survived by three sisters and two brothers: Pamela Engel of Wabash, Ind.; Mary Linda McNairy of Red Wing, Minn.; Christina Kettner of Saginaw, Mich.; David Kettner of Melrose Park, Penn.; and Stephen Kettner of Kalamazoo, Mich. He also is survived by several nieces and nephews.