When 21-year-old Lauren Drain found herself in a shabby apartment in a rough part of Topeka, abandoned by her family, her mind couldn’t accept what had happened. “I truly thought my banishment would only last for a month or so,” she writes. Only when she happened upon her father in public and he refused to acknowledge her did she begin to understand that she has been completely and permanently disowned for running afoul of her church's whims.

Seven years earlier, Drain’s family had moved across the country to join the Westboro Baptist Church, the Topeka-based cult known for its “God Hates Fags” signs and picketing the funerals of fallen U.S. soldiers. Until then, Drain had a more ordinary teenage experience: excelling in school sports, more excited by boys than religion. She was skeptical, even hostile to her father’s growing obsession with Westboro, especially when it drove him to pull her out of high school and place her under “house arrest” when he discovered her budding relationship with a classmate. But eager to make peace, she attended her first protest, where she was impressed by the confidence, passion, and encyclopedic knowledge of world affairs exhibited by the Westboro girls her age. “There was something to it,” she writes. “We moved people to ask us lots of questions, even if they screamed those questions at us. This meant we had some access to knowledge that they didn’t.”

Drain quickly become friends with Megan Phelps-Roper, a few years older and then the evident heir to the small, independent church founded by her grandfather, Fred Phelps, in 1955. The church has about 40 members, most of them also members of his extended family. The 83-year-old patriarch preaches a mutant, virulently homophobic fire-and-brimstone breed of hyper-Calvinism that insists God has chosen only a few elect Christians (mostly Phelpses) and hates the rest of the world with a burning passion. Members see it as their duty to inform the rest of us of our impending damnation, not to convert the damned but to ensure their own salvation. To effectively spread that warning, they show up at sensitive events like the funerals of U.S. soldiers and victims of the Sandy Hook massacre, and 9/11 memorials to attract media attention with outrageously offensive signs and slogans.

As Drain went through high school, the church’s behavior-policing regime felt increasingly oppressive and bizarre to her, and she saw herself being singled out despite her best efforts to please the Phelps family. Finally, after her own family discovered she’d been chatting online with a young man from Connecticut and informed the church, she was formally banished. “There is no hope,” her father said at a church meeting to decide her fate. “I am done with her!”

Every fundamentalist movement has deserters, but Drain found herself in a less common position: that of the young believer thrown out into the world against her will. Banished: Surviving My Years in the Westboro Baptist Church co-authored with writer Lisa Pulitzer, is her account of her years growing up with “America’s most hated family,” as one British filmmaker labeled them. The book offers a straightforward retelling of the facts, but it provides important insights into how fundamentalist movements attract and reprogram eager seekers, and the psychological effort required for survivors to adapt to life outside their reality-distortion field.

The book is, in a way, a story about her father, an outspokenly atheist rebel who married a Catholic girl and pulled her away from her religious family. Steve Drain was energetic and intellectual, but careened between passions, sometimes putting his family in difficult situations. He stayed in graduate school long past the end of his funding, racking up debt that would crush the Drains for decades. After briefly coming under the influence of a local fundamentalist, he reverted to his rebel ways, playing rock music and drinking with his buddies at the Drains’ home. After he finally graduated with his MFA and moved his family back to Florida for a job at the Home Shopping Network, he began work on an investigative documentary of Westboro he called Hatemongers.

Drain’s description of her father fits a common profile of potential fundamentalist: a “lost soul” in search of a grand explanation, with a thirst for life and a bottomless appetite for higher learning. “I don’t know if he had a clue what he wanted to do, but he told me he was seeking some type of truth,” Drain writes. “He took some philosophy, some civilization, and some religions courses—all of the subjects he chose had a spiritual or metaphysical bent.” Like many fundamentalist Christians in the U.S., his path to religious extremism began with a searching intellect and a sense that America’s consumer society didn’t have satisfying answers to the deepest questions about how one should live.

But despite what Drain describes as her father’s winning charm and his earnest searching, he had a chilling dark side: obsessive and controlling, he hit her, shoved her, and called her a “whore” for talking to a boy she liked. The violence preceded his involvement with Westboro, and seemed to have more to do with his panic about controlling his family than his religious ideology. He was so abusive that one day, terrified, Drain called Child Protective Services on the family’s cordless phone from the front yard. “I just needed my father to know I was serious about defending myself from his physical bullying, and I was reaching my breaking point,” she writes. When her father found out, he forced her to call back and tell CPS she had been lying, and no one from the agency followed up. Drain was pulled out of high school and forbidden from leaving the family’s house in Florida. Though her mother occasionally pleaded with her father to stop berating her, she almost always kept quiet or accused Drain of bringing on the abuse with her rebellion.

The Phelps family, too, manifested a paradoxical blend of intellectual curiosity and abusive behavior-policing. In many ways, they cut against the common understanding of fundamentalists as Bible-reading bumpkins who’ve never seen the inside of a secular classroom. Fred Phelps and several of his children have law degrees and run the successful Phelps-Chartered law firm in Topeka. In Drain’s account, Phelps’s daughter Shirley Phelps-Roper, who has become the de facto leader of Westboro, comes off as a veritable superwoman who somehow works at the firm, manages virtually all the church’s accounting and media relations, micromanages members’ lives, parents 11 children, and always made time to counsel Drain when her own parents were too distant to notice her. Phelps-Roper’s children, including Drain’s close friend, Megan, made the highest grades at their public high school in Topeka, and were generally acknowledged to be more literate in history and politics than most adults.

But these impressive achievements serve a sinister purpose. Phelps-Roper uses her energy as an administrator and parent to keep tight control over Westboro members, especially her children, who follow her example in loudly denouncing “fags” and “fag enablers” like Tyra Banks. Though Drain seems grateful for the genuine concern and guidance Phelps-Roper extended to her, it’s difficult to take even a glance at her Phelps-Roper’s Twitter feeds without getting nauseous.

While Drain doesn’t exactly provide a satisfying reason why Westboro’s extremism appealed to her formerly atheist father, it’s clear that he was enamored with Phelps-Roper and driven by an overwhelming desire to impress her. Almost immediately after making contact, his critical documentary began to transform into pro-Westboro propaganda, described on YouTube as “showing the lighter, more funny side of this very unusual cult.” In many right-wing Christian movements, the energy and confidence of people like Phelps-Roper provide a powerful sense of identity, of self-definition against the surrounding culture that can be intoxicating. Inside Westboro, Phelps-Roper’s seeming omnipresence in church members’ lives helps create a bond that is both communal and intellectual: members forge intense relationships debating doctrine, admonishing one another on how to live, and building up each other’s defenses against the outside world.

Unlike in many other cults, young Westboro members aren’t isolated from the world. They all attend public schools and have nearly uncensored access to television. They’re all on Twitter. Westboro adults use every profanity in the book in everyday conversation. Somehow, even amid the rush of hormones and social pressures of high school, most of their teens don’t break away. But Drain’s book hints at a sociological crisis that could be breaking the church apart: the lack of church-approved partners for Westboro’s upcoming young adults, most of whom are too closely related to marry one another. (Drain’s family is one of very few in the church not related to the Phelpses.) Sensing the younger generation’s alarm, Westboro leaders have spun out increasingly bizarre edicts on relationships, including, Drain writes, a blanket condemnation of marriage.

It may be sex, as well as growing doubts about the harsh regime inside Westboro, that’s motivating young members closer and closer to the center to defect. Four of Fred Phelps's 13 children had previously left the church, as did Shirley’s son, Josh, who met a girl at his job at Sears. On February 6, just before the release of Drain’s book, Megan Phelps-Roper, now 27, and her 19-year-old sister Grace, announced that they, too, had made their escape. Like Drain, who is now engaged and works as a nurse in Connecticut, they expressed regret and sorrow for having been a part of Westboro’s hate. But they face the overwhelming task of building a new identity, entirely cut off from the world they’ve known.