Before I ask the question: I've already looked at this one and don't feel that the answers cover mine.
Background: I "learned" the mathematics relevant to electronic engineering several decades ago. That is to say, I learned how to use the mathematics, but wasn't expected to prove the theorems, and I didn't work enough on it to do so. As a result, I spent a lot of time floundering around in differential equations. I've always regretted this, as I think I'd have enjoyed the maths more than the engineering if only I'd studied it properly. So now, I'm trying to learn mathematics properly, or at least some of the areas I'm interested in.
This means I'm not on a course but need suitable textbooks. Searching on Amazon and suchlike tends to bring up reviews of variable quality and opinions which depend very much on the personality or learning style of the reviewer, while I want recommendations that suit the way my mind learns things. Also there are pitfalls such as ending up with a very comprehensible book that uses antiquated terminology, so you understand the material but effectively in a "foreign language".
Is this site an appropriate place to ask for book recommendations, or perhaps opinions on a book I'm considering getting? My impression is that it would be off-topic (or at least borderline) on MSE, and that if I ask about this in their Meta they'll say they want questions about msths, not about books, and that book questions are opinion-based and therefore off-topic.
My questions are likely to be things like "I obviously need a much better understanding of vector calculus. What book might help specifically with that?" or "Do I need a more up-to-date book on analysis than this Kolmogorov one?"