I have been meaning to ask this question for some time, and have been spurred to do so by Georges Elencwajg's fantastic answer to this question and the link contained therein.
In my free time I enjoy reading historical accounts of "recent" mathematics (where, to me, recent means within the last 100 years). A few favorites of mine being Alexander Soifer's The Mathematical Coloring Book, Allyn Jackson's two part mini-biography of Alexander Grothendieck (Part I and Part II) and Charles Weibel's History of Homological Algebra.
My question is then:
What freely available resources (i.e. papers, theses, articles) are there concerning the history of "recent" mathematics on the internet?
I would like to treat this question in a manner similar to my question about graph theory resources, namely as a list of links to the relevant materials along with a short description. Perhaps one person (I would do this if necessary) could collect all the suggestions and links into one answer which could be used a repository for such materials.
Any suggestions I receive in the comments will listed below.
Suggestions in the Comments:
[Gregory H. Moore, The emergence of open sets, closed sets, and limit points in analysis and topology]