The bottom line: Access to education, higher-paying jobs and marital status all make a difference, and vary tremendously across faith groups.
Jews' median net worth was $423,500, according to a 2004 U.S. Department of Labor survey analyzed in the book, nearly five times higher than the population's median net worth of $86,000, and nearly 19 times higher than black Protestants' median net worth of $22,800.
Only 4 percent of mainline Protestants and white Catholics live below the federal poverty line, compared with 26 percent of black Protestants, 18.8 percent of Latino Catholics and 8.7 percent of evangelicals.
Why? According to the study, Jews and mainline Protestants are most likely to have earlier access to financial assets, while black and evangelical Protestants are most likely to be permanently asset-poor.
Author Lisa A. Keister, a sociologist at Duke University in Durham, N.C., and director of the school's Markets & Management Studies program, said "religion is the key factor" affecting financial wealth because it influences life opportunities and decisions that impact wealth.
Approximately one in five mainline Protestants and one in three Jews have advanced degrees, compared with just 4.2 percent of black Protestants and 6.4 percent of Latino Catholics, according to 2004 Department of Labor data. About a quarter (26.3 percent) of mainline Protestants held managerial or administrative positions, compared with 16.1 percent of evangelical Protestants.
Marital status also makes a difference: 2.2 percent of Jews are divorced, compared with 17.2 percent of evangelicals, according to the 2004 survey. On average, black Protestants have their first baby at age 22, while Jews are 30 when they first become parents.
Keister also found that religious groups that are more inclined to let spiritual convictions directly affect their careers and spending habits are less likely to be financially wealthy.
Evangelicals, for example, are nine times more likely to let religion influence their career choices than Jews, according to data collected from Gallup's Economic Values Survey. Evangelical and black Protestants were more likely to pray about financial decisions and find financial teachings in the Bible than mainline Protestants and Jews.
Evangelicals and black Protestants were most likely to say the church was the most important charity and that they should give money to religious causes. Evangelicals gave the most to religious causes, according to Gallup data, followed by Jews.
Among evangelicals and black Protestants especially, "there's a strong belief that their money is God's money," Keister said. The Rev. Bob Louder, founder of Christian Financial Ministries in Marietta, Ga., said that's a common perception amongst his evangelical clientele.
"The Bible says that wealth is so much more than just money," he said.
But Bob Barber, CEO of the Christian Financial Association of America in New Braunfels, Texas, disputes Keister's claim that evangelical Protestants are generally more financially challenged.
"What world is [she] hanging out in?" he asked. "Eighty percent of [my prospects] are totally debt-free, their finances are in great order and they have good cash reserves."
Keister said the book isn't meant to be critical.
"[Evangelical and black] Protestants say they are giving money to their church and friends in need rather than keeping it in their own bank accounts," Keister said. "You might ask, 'Is that really such a bad thing?' "