What math textbooks used in the late 19th or early 20th century are still great right now?Something like G.H Hardy's <i>A Course of Pure Mathematics</i>
Dover offers a lot of those classics:<p><a href="https://store.doverpublications.com/by-subject-mathematics.html" rel="nofollow">https://store.doverpublications.com/by-subject-mathematics.h...</a>