I started the EdX MicroMasters in International Law last week and it's very interesting. I'm getting an inkling of what legal reasoning feels like from the inside. So far, it seems like really, really careful reading and reasoning. In preparation for the course I was reading a textbook on the same but the readings and video transcripts are as good on the topics they cover, though less exhaustive. It's given me a very slightly less Realist take on International Relations for one.