I recently finished reading Going Clear and wanted to read more about Scientology because it is absolutely amazing how much has been covered up about this pseudo-religion. Beyond Belief doesn't go into specifics about the actual philosophy and teachings of Hubbard. Instead, Hill poignantly relates her experiences growing up surrounded by the Church. I would suggest reading Going Clear if you want more details about the history of Hubbard and the teachings of Scientology.
Hill describes a childhood that reads out of a science fiction novel or another country. Separated from her parents, who were both devoted to the Church, she was forced to do manual labor and live in a militaristic-like culture along with other Scientology children. All education was centered on Hubbard's writings, with little focus on critical thinking, and hyperfocus on memorization. She grew up thinking she could make a difference, but realized over time that everything was arbitrary and dishonest in her world.
It is interesting to see Hill evolve throughout the novel, and how she begins to question her loyalty to the Church. The contrast between the ordinary "rank-and-file" Sea Org members and public Scientologists and celebrities, is enormous. The members of the Sea Org are practically slaves, working on less than 50 dollars a week. The individuals in charge act like third-world dictators, creating a hostile and demanding environment, while covering up any possible scandal. Scientology constantly demanded donations and would require all members to buy Hubbard materials, while putting on grand displays of wealth and opulence. There doesn't seem to be any religious experience going on here. Reading about Hill's experience with auditing makes it seem akin to an Ouija board.
Because this book is from Hill's perspective, you won't be getting a full idea of what was happening in Scientology at the time. However, I like that she stays true to her own experiences and doesn't speculate on what she could not know.