Hello everyone! This is my first post on the forums so I hope I'm not posting this in the wrong section. I have been working through Apostol's Calculus Vol. 1 and so far I've been enjoying it a lot. I'm about to finish the 5th chapter, and while I would ordinarily wait until I was almost done with the book, I find that it would be easiest for me to get one or two books earlier than I had planned. I am definitely planning to buy the second volume of Apostol, but I would appreciate any advice on what the second book could be. I understand that linear algebra would be a beneficial topic to cover, and have considered Axler's "Linear Algebra Done Right". However, I see that Apostol covers linear algebra in his calculus books and I'm afraid that most of the material would be repeated. I also looked at Artin's "Algebra" and I would love to introduce myself to the topic of abstract algebra. If my experience is relevant, I am self studying this material and have only had access to math beyond high school through this book. Thank you!