The Three-Body Problem is a scientifically plausible book about human contact with aliens. It was a very good read.
The book is split between Maoist and modern China. It has some interesting historical vignettes about the cultural revolution, though if you're already familiar with the history, you probably won't learn much since the book doesn't go very deep.
Throughout the book, though, are scientific tidbits that you probably don't know unless you have a doctorate in physics and that are explained in a very easy to understand way and in a way that is relevant to the plot. I learned a bunch from that. The science in the book is mostly theoretical. For instance, there is some discussion of eleven dimensions, which has been postulated in string theory. There are also fancy nanomaterials and systems with multiple stars and ways to use the sun as a big amplifier. All of that happens along with descriptions of an alien culture and their first contact with humans.
This book is interesting, educational, and a fun read. I highly recommend it!