Reverend Ira Sylvester Caldwell's missionary work took him and his family deep into the region commonly referred to as the Bible Belt. His son, Erskine, was at his side on innumerable home visits with the elderly, sick, and poor of Georgia, the Carolinas, Tennessee, Virginia, and Florida. By the time the younger Caldwell left home at seventeen, he had also witnessed such varieties of religious experience as "Church of God all-night camp meetings, Holy Roller exhibitions on splintery wooden floors, primitive Christian baptismal immersions in muddy creeks, Seventh-Day Adventist foot-washings, Body of Christ blood-drinking communions, Kingdom of God snakehandlings, Full Redeemer glossolalia services, Fire Baptized Holiness street-corner rallies, Catholic mass at midnight on Christmas Eve, the rituals of Jewish synagogues, and . . . philosophical lectures in Unitarian churches."

Decades later, Caldwell drew on this fertile background when he toured Georgia and neighboring states in order to hear firsthand from ministers and churchgoers about how southern Protestantism was faring amid the social upheaval of the mid-1960s. Deep South offers a rich mix of anecdotes, memories, interviews, and observations that point to what may be the true essence of southern spirituality.