With more speaking invitations than he can accept, author Brian McLaren at age 56 is enjoying the success he sought when he left his Maryland pastorate in 2006 to write books full time. But as his 13th book goes on sale in September, McLaren isn’t entirely content. Evangelical institutions seldom invite him to speak anymore, he says, even though he comes out of their tradition and wants to engage them in dialogue.

“Among conservative evangelicals, I became a kind of has-been,” says McLaren, author of Why Did Jesus, Moses, the Buddha and Mohammed Cross the Road? Christian Identity in a Multi-Faith World (Jericho/Hachette, Sept.). “It’s unfortunate because a lot of things I write about have special relevance to evangelicals. There’s a lot [in my books] that could help them.”

McLaren’s habit of assigning new meanings to classic Christian doctrines has made him a darling of theological liberals and a punching bag for theological conservatives. When he posited in A New Kind of Christianity that the church’s traditional view of salvation is corrupt and unbiblical, Southern Baptists denounced him as a “wolf” and an “apostate.” Book sales surged, as did speaking invitations from liberal Catholic groups and mainline Protestants.

In his new book, McLaren asks: what is the relationship between Christian identity and hostility? The church has long fed religious rivalries, he argues, but that’s not what Jesus would do. “The traditional narrative of who goes to heaven and who goes to hell sets up human society as divided” between a blessed minority and an unblessed majority, McLaren says. “If we fit ourselves into that, I can’t see how that belief won’t produce huge byproducts of hostility and violence.”

McLaren grew up as a self-described “hardcore fundamentalist,” but he came to discover more in the Bible than he’d been taught to see. An English teacher who felt called to ministry, he led a non-denominational church in the Maryland suburbs for 24 years. Still, questions nagged. He wondered: rather than liberate, do church teachings somehow reinforce rivalries and imperial thinking?

Because McLaren seeks to rehabilitate rather than dismiss classic ideas, such as original sin, he can be difficult to categorize. McLaren loosely claims the “progressive evangelical” label, but many evangelicals say he’s left their fold. He’s seen as an “emergent church” leader, but that movement is too diffuse and unorganized to give him a well-defined home. He now attends an Episcopal church in Florida.

McLaren’s publishing career reflects his transience across categories. His publishers have included Jossey-Bass/Wiley, Zondervan, HarperOne, and now Hachette/Jericho. Since the new Jericho imprint, while Christian, targets readers who don’t fit into traditional religious categories, he says, it might be a good fit.

“My readership is kind of all over the map,” notes McLaren, who’ll be doing a 13-city book tour. “We’re gathering a new readership rather than fitting into an existing one.”