A great mathematician he was, the following Wikipedia page will give you a number of mathematics books which you can start to work on at any stage.
A must follow for all true lover of mathematics.
Bourbaki’s main work is the Elements of Mathematics (Éléments de mathématique) series.
Springer List of the books. [ http://www.springer.com/us/book/9783662437056 ] [find under “about this book” heading]