After reading this article[1] and the HN conversation about it[2], I realized I didn't know much about the theory or evidence around dark matter. I'd love to know more. What should I read as an introduction? I'm not trained in physics, but I've read Einstein's "Relativity" and Brian Greene's books. I'd love "popular" material along those lines.

[1]: https://aeon.co/essays/why-its-time-to-take-alternatives-to-dark-matter-seriously [2]: https://news.ycombinator.com/item?id=23665330