FOR nearly 60 years, the Gallup Organization has traced Americans' attitudes toward religion through answers to questions about faith in God, belief in heaven, and use of the Bible.
What's remarkable about the scores of surveys on the subject, says George Gallup Jr., head of the nation's best-known polling firm that bears his name, is ''the stability of religious practice and belief'' over the years.
Since the polls about religion began in the late 1930s, more than half of respondents have consistently said religion is ''very important'' in their lives. The figure was highest in 1952, when 75 percent of Americans polled by Gallup gave that response. The low point was 1987, when it dipped to 53 percent. But the number has been climbing since then.
''Always,'' Mr. Gallup says, ''the challenge is to dig deeper -- to what degree are people transformed by faith and changed in the ways they relate to others?'' What Gallup calls ''the inner life'' could be a new frontier for survey research, he says. At present it's ''pretty much neglected in this country.''
But how do you get at that inner life through survey questionnaires? One way, Gallup suggests, is to probe the nature of people's ''religious experiences.'' An ''ongoing one-third'' of Americans say they've had such experiences, he says -- a finding that has surprised him, he says.
The experiences include conversion, near-death episodes, and revelations from the beauty of nature. They can be sudden, Gallup says, or more gradual, but always there's a discernible point when something happened. He's determined to try to ''understand the nature of these experiences -- what prompted them.'' He'd also like to study such experiences abroad.
''The implications for creating stronger bonds between people are tremendous,'' Gallup says. He says his surveys have indicated people's religious experiences ''invariably move them in a positive direction.''
Gallup says the work done by his Princeton Religious Research Center, the branch of the polling organization that concentrates on this subject, suggests ties between religious commitment and self-esteem, optimism, and health. At the deepest level, such commitment reaches what Gallup might call saintliness.
''The Saints Among Us,'' a 1992 book by Gallup and his colleague Timothy Jones, shows examples of such commitment. Such people are ''twice as likely to be involved with charitable activity,'' says Gallup. ''They're more giving, and forgiving, and happier.''
Identifying such people took a lot more than questionnaires. Researchers did in-depth interviews and talked with friends and neighbors of the individuals profiled in the book.
It takes ''a number of questions to even get close to legitimate findings'' about the depth of religious feeling, Gallup says. In working on the ''Saints'' book, he and Mr. Jones came up with a series of attributes common to these people: they daily try to stay in touch with God, they translate belief into action, they experience the grace of God in forgiveness, and they want a growing faith, not a static one.
Gallup says there's no ''prototype'' of such ''saints.'' But he adds that he has known a few, and the ones that come most readily to his mind are the elderly members of an all-black church in a poor section of Texas where he worked for a time in the 1950s, while he was considering entering the Episcopal ministry. Despite their own lack, the members selflessly put others and their community first.
The Gallup surveys, in fact, indicate a connection between economic level and religious faith: Of those with yearly incomes less than $20,000, 2 out of 3 say religion is very important to them, versus less than half of those earning $50,000 or more.
Concerning the interaction of religion and politics, currently a hot issue, Gallup focuses less on the much-publicized influence of the ''religious right'' than on the impact of religion in moving people toward volunteer work that can alleviate suffering in society. But for all those working in prisons or in AIDS clinics, he says, ''a lot of church members avoid the margins of society, and people there need religion most of all.''
How do Americans conceive of God? About 85 percent believe ''in a personal God,'' says Gallup. ''They feel the Lord in their lives.''