Thank you for this already very comprehensive list! I can think of a couple of recent books that are not yet on this list, e.g.:
- Mathematics and Chess (Dover Recreational Math)
- Loving and Hating Mathematics: Challenging the Myths of Mathematical Life
- The Man of Numbers: Fibonacci's Arithmetic Revolution
On this website (http://popsciencebooks.com/category/mathematics-2) there are also a couple of interesting math books.