When Laurel Thatcher Ulrich, a University of Utah graduate, won the 1991 Pulitzer Prize for history this week, her initial reaction was disbelief.

"My editor at Knopf called me and just screamed in the phone `Pulitzer!' and I said `What?' I was so dumb that I didn't even realize that the Pulitzers were given out this time of year. By the end of the day I finally saw the list in the newspaper and it looked to me like one of those joke things when people paste your name in the paper."Ulrich, an associate professor of history at the University of New Hampshire, won the coveted prize for her 1990 book, "A Midwife's Tale: The Life of Martha Bal-lard, Based on Her Diary, 1785-1812."

Ulrich is one of only three Mormons to have won the Pulitzer Prize, a signal honor that also went to Merlo Pusey, for his biography of Charles Evans Hughes in 1952, and Jack Anderson, who won it for national reporting in 1972.

She is also the author of the highly acclaimed "Good Wives: Image and Reality in the Lives of Women in Northern New England, 1650-1750" and of various scholarly articles and personal essays.

A native of Sugar City, Idaho, Ulrich received a bachelor's degree in English from the University of Utah, a master's, also in English, from Simmons College in Boston, and a doctorate from the University of New Hampshire. She and her husband Gael have five children, one of whom still lives at home.

In many ways, Ulrich is an unlikely candidate for the distinguished prize. Eleven years elapsed between the time she earned her bachelor's degree and the time she earned her master's while she concentrated heavily on raising her family and on church and community activities. By that time she was 33 - and by the time she received her doctorate she was 42 - an academic late bloomer.

She thinks now that "it was not such a bad career path, especially for anyone in the humanities. The problem with young students is that if you haven't lived very long there are some things you just can't get. It's a rare thing in our world to put together a rich personal life and a rich professional life."

Her first book, "Good Wives," was originally her doctoral dissertation and was published in 1982 by Knopf. It was so highly acclaimed that she received instant recognition in the scholarly world.

When she was 42 she began the Martha Ballard project and finished it when she was 53, an age commensurate with her subject, who started keeping a diary at the age of 50.

Martha Ballard was a housewife, midwife and healer in the Kennebec River towns of Hallowell and Augusta, Maine, who delivered 814 babies in the 27 years covered by the diary.

The diary brings historians closer to the realities of ordinary life in preindustrial America than they have ever been before. Ballard not only talked about births and deaths, but the "dailyness" of life - the marital relationship, raising children, growing old, religious devotion, scandals - the things that often escape the historian.

To tell the story, Ulrich not only went deep into the sources of the period that help the reader understand the diary, but also became an expert on 18th-century medicine and midwifery.

Now she is about to begin a sabbatical from her teaching duties in early American social history to start something entirely new - a study of textiles in Colonial New England. She is not interested in production, but "the language of clothing and the way people design themselves through it."

If it leads to another award-winning work, it will be another surprise.