The motto of Highland Park High School in Dallas, Texas is “Enter to learn. Go forth to serve,” but apparently, if you’re a high school student who wants to learn anything about spiritual awakening in Hermann Hesse’s “Siddhartha,” cultural identity in Toni Morrison’s “Song of Solomon” or structural economic inequality in David K. Shipler’s “The Working Poor: Invisible in America,” you’d better do it on your own time.

Those books and four others are on the list of books banned from the school’s required reading list (and, hence, are banned from being taught in Highland Park High's classrooms) by the school district after parents’ angry emails to board members demanding that they be “suspended” got results. (The books do not, however, appear to have been banned from the school library.) The news broke just ahead of Banned Books Week, an annual awareness campaign that spotlights books that people attempt to ban from schools and public libraries on the grounds that their content is offensive.

Jeanette Walls’ “The Glass Castle” is also on the list of books banned from the classroom, and Walls is set to deliver the keynote at the school’s literary festival in February 2015. It is unclear if she will withdraw -- at this time, she is still listed as the keynote speaker on the festival’s website -- but she said that she was disappointed about the decision to ban her memoir, which includes stories of her dysfunctional childhood rife with her parents’ alcoholism and mental illness.

“My book has ugly elements to it, but it’s about hope and resilience, and I don’t know why that wouldn’t be an important message,” Walls told the Dallas Morning News. “Sometimes you have to walk through the muck to get to the message. What I worry is that in order to protect [students], we may be taking away the tools they need to protect themselves later on. “

The school district, at the behest of parents, cited the suspended books as inappropriate for a number of reasons, as reported by The Dallas Morning News: “Siddhartha” for its main character’s sexual encounters with prostitutes and because of the character’s having a child out of wedlock; “Song of Solomon” for its sexual content, including a storyline about incest; and the nonfiction book “The Working Poor,” which includes a young woman’s account of being raped in second grade and having an abortion as a teenager.

Other books banned include award-winning young adult novels “An Abundance of Katherines” by John Green (for sexual scenes) and Sherman Alexie’s “The Absolutely True Diary of a Part-Time Indian” (for strong language), which, as Aja Romano of The Daily Dot notes, “seems to spend more time on ban lists than it does on bookshelves.”

Not all parents are happy about the banning, and District Superintendent Dawson Orr and high school principal Walter Kelly have said that the banned books will be reviewed again by a committee of parents, teachers and students, which will probably take take several months, the Dallas Morning News reported. Highland Park High School’s approved list of books includes novels that are still considered subversive such as Gustave Flaubert’s “Madame Bovary” and Mark Twain’s “The Adventures of Huckleberry Finn.”

“This is not about banning books,” Tavia Hunt, a parent who objected to graphic sex scenes in books taught in English class, said to the Dallas Morning News. “No one is advocating that. We want the kids to have access to the books in the library. The problem is having obscene literature mandatory in the classroom and for discussion.”