arXiv.org was originally designed to be a repository for pre-prints of physics articles, but it has since been expanded to other disciplines. I recently discovered that even though most of the math pre-prints are out of my league, there is one category of math articles that I have a good chance of understand: math history.
The former historian in me has to point out, however, that for the most part, mathematicians writing history (of mathematics) is fascinating for the general “we are interested in math” audience. But historians will cringe at the teleology and absence of any culture in these narratives; they tend to be self-contained, internalist, and lack nearly everything that historians value in their craft.
There are really good historical works on mathematics written by mathematicians, I’m sure. But I guess I want to say that there are really good historical works on mathematics written by historians too. I would argue — from what little I’ve read in both realms — that these works by historians are often better, more considered, and more interesting. And the really good ones don’t skimp on the mathematics either, but delve deep into the mathematics, and relate the mathematics to culture.
A few from the top of my head:
Karl Pearson: The Scientific Life in the Statistical Age (Ted Porter)
Masters of Theory: Cambridge and the Rise of Mathematical Physics (Andrew Warwick)
Mechanizing Proof: Computing, Risk, and Trust (Donald MacKenzie)*
*Actually, this is a sociology of mathematics book.