He is the man most responsible for founding the Progressive National Baptist Convention (PNBC)—the denomination that provided a church base for Martin Luther King Jr. But you won't find his name noted in many history books. In fact, most black Baptists will credit King and New York preaching legend Gardner Taylor with starting the denomination. The credit, however, rightfully belongs to L. Venchael Booth, whose story is finally told in a recently released book about the PNBC.

In November 1961, Booth persuaded a cluster of disaffected members of the National Baptist Convention U.S.A. to leave their massive denomination—then and now considered the mother of all black Baptist groups—and form the PNBC. The new entity they agreed to launch that chilly day at Booth's Cincinnati church has since become the second-largest black Baptist group in America.

Booth doesn't strike one as a maverick or a rebel. But 40 years ago, those were fitting descriptions for a man who decided to take on what was one of the black community's most powerful institutions. "It was not folly or a desire for power that propelled me to move ahead with calling for a new convention," says the 82-year-old preacher. "It was a belief that our convention should inspire us to do greater kingdom building."

The history of African American Protestantism is loaded with sensational stories—from AME founder Richard Allen's unceremonious departure from the white Methodist church to Church of God in Christ organizer Charles H. Mason's Pentecostal epiphany at the Azusa Street revival. In more recent times, the history has been less heroic and more political. Some of the liveliest episodes have taken place among black Baptists, who formed slews of denominations ...