Henderson is a peppy, unassuming man in his early 50s, a Jerry Falwell-trained Baptist minister. After serving for many years as the spiritual leader of a megachurch in suburban Minneapolis, he left the pulpit and founded Strategic Renewal, a nonprofit organization that holds “prayer summits” and how-to-worship seminars around the country. (Henderson was also a contributor to the magazine Pray!, which recently went out of business.) “The fact is, most pastors never learn how to really pray,” he explained. “They get to the seminary, and people just assume they know how to pray. But that’s not true. Prayer is a lot more than reciting words. It requires mastering both theory and technique.”...