Pew Forum on Religion & Public Life offers in-depth religious biographies on its Web site that tell the candidates' faith stories and explain their views of how religion should impact public life.
John McCain was a prisoner of war in North Vietnam when a captor showed him unexpected mercy, affirming his faith.
Sarah Palin was baptized Roman Catholic, belonged to a pentecostal church for most of her adult life and now attends several nondenominational, evangelical churches.
Barack Obama was a community organizer in Chicago when a black church helped him embrace faith despite his serious doubts.
Joe Biden was born to Irish-Catholic parents and briefly considered becoming a priest when he was a young student.
For updated coverage, news and analysis, visit the forum's Religion & Politics '08 section.