Ever since her days on the ground as a war reporter in Central America in the 1970s and ‘80s, Sara Miles has dug her hands into everything she does, gotten mixed up in the material, the earthy. Back then, reporting on conflicts and revolutions, she was not a militant atheist, but she didn’t give religion much thought.

Now an Episcopal lay liturgist and preacher in black cassock, on Ash Wednesday Miles takes to the streets of the Mission District of San Francisco, marking those she meets with the ashes of Lent, according to the biblical proverb: "You are dust and to dust you shall return."

As with the act of smudging foreheads with ashes, Miles came to Christianity physically rather than through doctrine or revelation. She tasted her way into following Jesus. "The way I first experienced God was to have him in my mouth," Miles says, referring to the moment she first took the bread and wine of Communion and began the process of her "annoyingly ongoing conversion,” recounted in Take This Bread: A Radical Conversion (Ballantine, 2007). "I ate a piece of bread, drank some wine, and Jesus happened to me.”

Miles describes her faith as orthodox, sacramental, and unapologetically experiential. "I don't mean to be anti-intellectual, but my own understanding is that God is not a logical proof, not a good idea, or about moral principles and platitudes," she says.

Instead, she finds God in the city, her convictions on its sidewalks and in its people. In her new book, City of God: Faith in the Streets (Jericho, Feb.), Miles interweaves characters and portraits of San Francisco to bring her urban ministry to life.

Though not originally from San Francisco--a small city vivid in its multiplicity--Miles has made it home for more than 20 years. "The Mission in particular is a place that is deliberately and profoundly, 'mixed up'," she says. "There is a surprise around every corner." She adds, "Though nominally a 'secular city,' you can constantly be surprised [there] by places, arches, people, niches, and corners that are 'faith-filled'. That's incredibly engaging and how I want to live; it's where I find God."

Coming both to faith and her city as an outsider, Miles is drawn to aspects of each that are corporeal. She appreciates traditions and institutions that have physicality to them—such as the rituals and sacraments of the Episcopal Church--that "haven't been flattened out and are still rich, inexhaustible, and surprising."

Holding to the premise that "God has left the [church] building," Miles believes she does not take faith to the streets, but finds it there. "I am in this privileged position to get to see what people's experience of faith and God is, and for each person it is slightly different." In her book she aims to voice this urban canon, this discovery of people who are "hungry for something that's real."

Of marking foreheads with ashes, Miles says the yearning for belief that is solid and can be touched is part of the draw of that ritual. "It's stunning how many people want to be told they are dust and that they will die," she says. "The chronic lie of our culture is that people don't die. But people want to know the truth."