I'm a highschool senior, I;ve been spending the past few months learning some fairly interesting mathematical topics. I've come to the end of the number of books I bought awhile back, whose topics include Calculus up to Taylor and Macluarin Series, Linear Algebra up to Eigenvalues and Eigenvectors, and Diffirential Equations up to using Lapacian Transformations to solve diffirential equations (and some systems of diffirential equations). I have no idea where to turn next, but the summer is coming up and I really want to use the extra time to power through a ton of new and interesting mathematical sub-subjects. I'm thinking I'm gona head in the diffirential geometry / topology direction, but I need some advice. Does anybody have any good reccomendations for books on these subjects? Like introductory type books and some intermediate books and then some advanced ones. The key here is that these books be accesible regradless of the supplement of attending a college class on the subject. I used books to learn previous mathematical topics, without the class supplement, so I hope it will work the same for this situation. Thanks in advance. Oh and Set Theory, a book on Set Theory is something I'm looking for also. I have a grasp on what it is and how it works, but I know I need a through intorduction into Set Theory if I want to study Topology