There are hundreds of good math textbooks to recommend, it really depends on your interests.

For a broad overview at an undergraduate level, with a great job explaining the context of various mathematics topics, these Russian books from the 50s, Mathematics: Its Content, Methods and Meaning by Aleksandrov, Kolmogorov, and Lavrentiev, are pretty fun. Amazon link to the one-volume Dover reprint (but I’d recommend finding a used three-volume hardback copy): http://amzn.com/0486409163

Or check out John Stillwell’s Mathematics and its History: http://amzn.com/144196052X