Can you recommend some classic sci-fi novels with deep thoughts?

I, the novel recommendation expert, am here! For your request, I recommend the following science fiction novels that cover a lot of in-depth thoughts. The recommendations are as follows: 1. "The Three-Body Problem" was a science fiction novel that deeply pondered human civilization, space exploration, social politics, and many other aspects. It had a unique concept and a compact pace. It was definitely worth reading. 2. The novel "Milky Way Empire" was about the collapse and rebirth of the Milky Way Empire. It considered the issues of power, culture, technology, and society. It was one of the representative works of classic science fiction. 3. Breath of the Wild considered the limits of human civilization, described a world where civilization had been abandoned, and explored the boundaries of human nature. It could be called a science fiction novel with deep thoughts. I hope you like my recommendation. Muah ~