Bikers converge at the Vietnam Veterans Memorial in Washington, D.C. Thousands flock to a Nevada desert to burn a towering effigy. And the hopeless but hopeful ill journey to Lourdes as they have for centuries. Although pilgrimage may seem an antiquated religious ritual, it remains a vibrant activity in the modern world as pilgrims combine traditional motives--such as seeking a cure for physical or spiritual problems--with contemporary searches for...