I have tried writing things I don’t want to forget, but I didn’t like it much. I have copied short quotes and added sticky notes at important parts, which I liked, but felt possibly not enough. I tried annotating, but it made me feel bad and disrespectful for the book.
Okay, for note-taking I think there are a few critical things to do:
Write down explanations of terms/names which you don’t implicitly understand the meaning of. Lenin is dragging Kautsky but you don’t know why or what Kautsky represented? Cool. Figure it out via Wikipedia, searching r*ddit, making a question here or on Hexbear about it etc. and write a summary of what “Kautsky” symbolises.
Write down questions and assumptions as they come up. “SPD will later betray the KPD” or “How does the SPD rationalise their collaboration with the Nazis? Is Thällman right about ‘social fascism’?”
Highlight key points and takeaways from the text. Stuff like interesting quotes, important details, the key learnings etc. All the stuff that you would put into a summary of the book if you needed to, basically.
You don’t have to do this in the book itself. You might want to write things down on a notepad or type it up in a word document. Depending on how in-depth you’re going, you may want to even go so far as to make it into something resembling a draft of an essay. Note that the very exercise of writing things out will reinforce your learning process so it doesn’t even need to be a permanent document tbh.