There aren't a lot of options for those looking for English language books in Mexico. However, there are a few good libraries and bookstores that may indeed prove handy. Anglo-Mexican Library Basic collection, good reference section. Benjamin Franklin Library Extensive collection with over 25,000 volumes on almost any subject.
Membership is free.
Bookstores Libros, Libros, Libros Excellent selection of books and magazines. Books can also be ordered from abroad. Good selection of used books at bargain prices. Book donations welcome. Profits go to charity work.