What are some good authors - or textbooks itself - of mathematics textbooks that focus on constructing elegant theorems, proofs, et cetera?
One example of author that writes that way would probably (and I say probably because I used one of his books only as a supplement, not as the main text) be Paul Halmos.
I am looking for real analysis, algebra and theory of numbers authors and textbooks, mainly.
It can also be authors/textbooks of physics books, but they must include mathematics teaching in their books. Also it doesn't have to be a very good book to study, I intend to use it as a way for recreational activities.