"What is real?" by Adam Becker. It doesn't touch much on general relativity if you are interested specifically in that, but it's a great read and gives you a bit of perspective how "modern" science works (I mean before the Internet, and back when we were actually moving forward..)

> Perhaps it's because matters can get quite political and subjective at that level.

Much more than I would have thought.

https://www.goodreads.com/book/show/35604796-what-is-real