She is India's most famous public figure, and its most mysterious. Her family name has been synonymous with national politics for half a century, yet many Indians are now seeing her in person for the first time. Her Italian roots remain anathema to many voters, and her personality is still an enigma to all but her closest associates.

Sonia Gandhi, the reclusive widow, daughter-in-law and granddaughter-in-law of three Indian prime ministers, has reluctantly taken to the hustings as a candidate for Parliament in elections that begin Sunday and continue for four successive weekends, ultimately determining who will lead this democracy of 1 billion people into the new millennium.

But Gandhi, 52, has not yet declared whether she will seek the prime ministership, and she agreed to seek a seat in Parliament only after aides persuaded her that she alone had the stature to unite their fractious Congress party and challenge the formidable popularity of Prime Minister Atal Bihari Vajpayee.

"She is the only glue in the party," said Jairam Ramesh, who writes campaign speeches for Gandhi. "India has so many fault lines of religion, caste, region, language. All Indians have a deep desire to find a leader who can transcend them." Gandhi, he added, is "still evolving . . . but she is the only nonpartisan figure we have."

For two weeks, Gandhi has been gamely if awkwardly campaigning--swooping into village fields and city parks by helicopter, giving brief speeches in her still tentative Hindi from heavily guarded platforms, offering her trademark "windshield wiper" wave and then vanishing again into the sky.

It is hardly a formula for getting to know the voters, but Congress party strategists hope it will add to the mystique and awe in which many Indians hold the Gandhi family and remind them of the ultimate sacrifices made by her husband, Rajiv, and mother-in-law, Indira, both of whom were assassinated.

Yet Gandhi, who entered public life only last year to assume the Congress party presidency, has revealed little about herself, granting virtually no interviews and saying only that she wants to follow her family's "tradition of service." In accordance with her wishes, many Congress campaign posters feature the party's symbol, a raised hand, rather than her face.

"She is a smart woman and a fighter, but her style is formal and deliberative," said Rajiv Desai, one of Gandhi's informal advisers. "The hallmark of the Indian political class is garrulousness, and she represents the very antithesis of that."

In contrast, Vajpayee, 76, a white-haired political veteran, has come charging out as the standard-bearer for his Bharatiya Janata Party (BJP). Every campaign banner features his avuncular grin. Every opinion poll shows his leadership--especially during the recent 10-week conflict in Kashmir along the Pakistani border--to be a key factor in the Hindu-nationalist BJP's soaring chances to win a solid majority of Parliament's 543 seats.

Moreover, although Gandhi constantly asserts her dedication to "mother India," BJP officials are working hard to remind the public she is a "foreigner" who did not become an Indian citizen until 1980 and never learned to speak fluent Hindi. This fact seems to bother many voters, even sophisticated Indians who send their children abroad to college and drive imported cars.

While Vajpayee has skirted the issue of Gandhi's roots, other BJP aides have struck aggressively. Last week, one indirectly compared Gandhi to former White House intern Monica S. Lewinsky; another suggested that her only contribution to India was bearing two children here. Some have suggested she has ties to unsavory Italian businessmen.

"This lady is a mystery to all of us," said K.R. Malkani, a longtime BJP politician. "She arrived from God knows where, and she presumes to lead a country where even the lowest government clerk needs permission to marry a foreigner. She is an Italian robot in an Indian sari."

Actually, Gandhi has lived in India for more than 30 years and spent much of that time as an intimate witness to its political struggles. After she and Rajiv Gandhi met as students in Britain in 1965, they married and moved to New Delhi, where his mother was prime minister. Gandhi dutifully assumed the role of bahu, or daughter-in-law.

After Indira Gandhi was slain in 1984, and then Rajiv in 1991, the shy widow secluded herself, raising two children in unobtrusive luxury. It was only when the BJP--a small party long associated with Hindu-first nationalism--began seriously to challenge Congress's longtime grip on power that aides began pressing her to assume a leadership role.

Her debut performances were stiff and indecisive. After Vajpayee had been in office a year, Congress engineered and won a vote of no-confidence against him last April. But Gandhi was unable to muster an alternative coalition government, leaving Congress in disarray and India facing its third election in four years. Then, after party members questioned her foreign origins, she quit the party presidency in a huff and had to be heavily wooed to return.

Now, in her reluctant role as a candidate for two parliamentary seats--India allows candidates to run in more than one district--Gandhi faces tough competition. In Bellary, an arid and poor area of Karnataka state where elections will be held Sunday, her BJP opponent is a feisty, folksy politician named Sushma Swaraj. Gandhi is also running in Uttar Pradesh, where the vote will be held later in the month.

Last week, as the two women crisscrossed Bellary, the contrast between their styles became starkly evident. Gandhi dropped in by helicopter; Swaraj shouted greetings in the local Kannada dialect. Gandhi spoke grimly of her family tragedies; Swaraj cracked puns on the name Sonia, which sounds like the Hindi word for "zero."

The audience response to both was tepid, reflecting a high degree of fatigue after so many successive elections. Some people said they knew little about Gandhi but would vote for "the hand" that had always fed them.

Others said they were unfamiliar with Swaraj but wanted to reward Vajpayee for his leadership, especially in the recent border conflict in Kashmir.

"I have heard Sonia's name since the time of Indira. I will vote for her because her family has done much for India," said Allah Baksh, a 40-year-old tailor, at a Gandhi rally in the town of Sandur.

In the nearby city of Chitradurga, Prabhu Prasad, a 45-year-old truck driver, said he had been impressed with Gandhi's speech but had one crucial, nagging doubt. "She seems intelligent, and she comes from a respected family," he said, "but something in my conscience tells me she's not ours."

Little by little, Gandhi has begun warming to the campaign. She held her first news conference ever several weeks ago, pounding angrily on the podium when reporters questioned her integrity. In speeches, she now coldly accuses the BJP of "standing on dead soldiers' bodies" to win votes.

Congress officials remain convinced that Gandhi is their best hope for a political comeback--in part because of her magical surname, and in part because other emerging leaders have been stifled from developing or punished for challenging the party line.

"Congress needs to come out of its stupor," said Ashwani Kumar, a lawyer who is acting as a campaign spokesman. "It needs to change, and Sonia Gandhi is the one who can change it."

CAPTION: Congress party backers hold up their hands, the symbol of support for their candidates, primarily Sonia Gandhi, the 52-year-old reclusive widow, daughter-in-law and granddaughter-in-law of three Indian prime ministers.

CAPTION: Many Congress supporters want the Gandhi dynasty to continue, and a few proudly show off a photo montage of Rajiv, Indira and Sonia.

CAPTION: Gandhi, who has been waging her campaign across India for two weeks, has the ear of women at a rally in Bellary, in Karnataka state, where parliamentary elections will be held Sunday.