Reading a book should not affect our religious beliefs. I am an Orthodox Christian, a devout believer. Reading books with different beliefs is not bad, just as it is not bad that other religions are taught in theological schools.
I found the book very interesting and wonderful in the sense that it promotes love. In many points, it aligns perfectly with my religious beliefs (e.g. God is Love, Apostle Paul), while in others it partially contradicts or even completely contradicts (e.g. reincarnation). However, it is full of moral teachings and I believe I benefited from it.
If someone does not have strong religious convictions, I think it would be better for them not to read such books. A book, the content of which cannot be controlled, should not be able to change our beliefs.
I emphasize that the author says: Keep what expresses you and throw away what does not express you.