Obama didn’t land in Jeremiah Wright’s church by chance, David Maraniss writes in “Barack Obama: The Story.” As a young community organizer in Chicago, Obama needed the help of local pastors, but he wasn’t a church member. Obama, “an inveterate doubter” by Maraniss’ account, felt pressure to join a church and a growing desire to explore his relationship with God.

A pastor working with Obama advised him to find a church outside the project’s boundaries to avoid alienating other pastors, and sent him to meet a preacher outside the district. That pastor referred Obama to Wright, whose Trinity United Church of Christ stood just across the street from the boundary.

“I used to tease Barack, ‘You joined a church as close to the boundaries as you could get,’” said the Rev. Alvin Love. Obama didn’t become fully engaged in Wright’s church until he returned to Chicago after his years at Harvard, “but the process started then, in October 1987,” Maraniss writes.

Wright helped Obama embrace Christianity, officiated at his wedding and baptized Obama and his two daughters. Obama quit the church after the preacher’s incendiary teachings became a political issue in 2008.

Maraniss’ book, on sale June 19, fills in details on Obama’s early years and family. A more nuanced portrait emerges of Obama’s maternal grandparents, whom Obama lived with from 1971 to 1979.

His grandmother, Madelyn Dunham, is widely remembered as a strong woman who worked her way up from secretary to become one of Hawaii’s first female bank vice presidents. Obama has painted his grandfather, Stanley Dunham, as a man with a wild streak early on who settled down to sell furniture and life insurance. Both are deceased.

In an interview with Maraniss, Obama said his grandmother, known as Toot, began drinking more and more as her responsibilities weighed her down.

“That’s where you started noticing her alcoholism,” Obama said. She would come home, “exhausted from work, tightly wound and go into her room.”

The book documents how little contact Obama had with his father even early on. Obama has written that he was separated from his father at age 2. But within a month of Obama’s birth, his 18-year-old mother had taken him to Washington state, where she attended college for a year. They returned to Hawaii in early summer 1962, when Obama was a year old. His father left the island for good that June.