The furor over mosque-building in Manhattan and Koran-burning in Florida reminds us that like it or not, religious differences continue to challenge civic peace. A new book, The Tenth Parallel, by journalist Eliza Griswold narrates her experiences on the 10th parallel, 700 miles north of the equator. This line of latitude runs through territories where about 60% of the world’s Christians and more than 50% of the world’s Muslims live. Griswold traveled this line for seven years, investigating religious relationships in Nigeria, the Sudan, Somalia, Indonesia, Malaysia, and the Philippines. Much of the conflict, Griswold notes, has “largely to do with population growth… [and the forms of these religions that are growing the fastest]… tend to be the most radical…” It’s a sobering assessment, but Griswold’s perspective isn’t completely negative. She observes that religious institutions sometimes provide necessary, basic care when states cannot and often promote a morality of care. You can read an interview with Griswold by Christian Science Monitor‘s Marjorie Kehe here.