What Americans don't know about religion is sometimes funny. For instance, when Jay Leno interviewed people on the street recently, someone told him that God made Eve out of an apple.

Our ignorance also makes for some astonishing statistics. Ten percent of us believe that Joan of Arc was Noah's wife. Seventy-five percent of us are certain that the Bible says, "God helps those who help themselves." Even evangelical Christians have lapses: 20 percent say they believe in reincarnation.

It should not be surprising, then, that most Americans don't know the difference between Shiite and Sunni Muslims. Most of us haven't read any Hindu Scripture, and we couldn't find the Buddha's Eightfold Path with a map.

In his new book, "Religious Literacy: What Every American Needs to Know — and Doesn't," Stephen Prothero, head of the religion department at Boston University, points out what Americans don't know and how it can hurt us. His book includes a religious literacy quiz that he says most of his beginning students fail at the start of an introductory course.

Because we are ignorant of the Bible, of our own faith (whatever religion we might practice) and of others' religious traditions, we stand to suffer politically, culturally and personally, Prothero says. We can't decode political speeches, we can't weigh religious arguments, we can't explain to our own kids why we disagree with others on a religious point, he explains in a telephone interview. We're even confused about our own beginnings.

"Ever since George Washington put his hand on a Bible and swore to uphold a godless Constitution, the United States has been both staunchly secular and resolutely religious," Prothero writes in "Religious Literacy."

The problem, Prothero argues, is an unfounded wariness of teaching religion as a secular subject. Only 8 percent of public high school students report that their school offers a class on the Bible.

"There are two ways to talk about religion," Prothero says. "The way we're most accustomed to is a Sunday or Sabbath school way, as a matter of personal faith. But religions are institutions, with histories and books that outsiders can read and ethical codes that outsiders can learn. There is as much knowledge to be gained about religion as there is about music, art and history."

Like it or not, religion has shaped and still is shaping American history, culture, politics and foreign policy, Prothero says.

"If you want to understand the upcoming presidential campaign, you have to know something about religion," he says. "Mitt Romney is talking about his Mormonism. John Edwards is talking about Jesus. Hillary Clinton is talking about the good Samaritan in the context of immigration reform."

Americans who are ignorant about religion are vulnerable to "being bullied," Prothero says, by politicians and by those in the news media who "give too much coverage to the crazy arguments."

"Between the crazy secular left and the crazy religious right, there is a really huge middle," he says. "That middle tends to be silent because we don't know enough" to talk intelligently about religion.

The diversity of religious expression in the United States is challenging, he says, but it is no excuse for nursing our ignorance.

"Our public debate about religion-inflected matters is dominated by people on the far left and the far right, who either think religion should be run out of politics or rammed down our throats," he says. "This leads to a kind of public discussion that is more heat than light."

What's a country to do? Prothero calls for public school classes that teach about religion and sacred texts by trained teachers who know their Constitutional responsibilities. In the meantime, he's compiled a dictionary of religious words, people, stories and symbols that fills 78 pages of his book.

If nothing else, he says, spend an afternoon reading two books of the Bible, Genesis and Matthew.

"If you read those two books, you get about 80 percent of the characters, phrases and stories that are used in American politics," he says. "It's a start."

And then, unlike a chunk of the American public, you'll know that Abraham Lincoln didn't deliver the Sermon on the Mount and that Sodom and Gomorrah were never married.

(Nancy Haught writes for The Oregonian in Portland, Ore.)

© 2007 Religion News Service