It was twenty years ago today ...

Understand

To mark the 20th anniversary of the (14 Aug 1991) commencement of hep-th@xxx.lanl.gov (now arXiv.org), I've adapted this article from one that first appeared in Physics World (2008), was later reprinted (with permission) in Learned Publishing (2009), but never appeared in arXiv.

• I trace some historical context and early development of the resource, its later trajectory, and close with some thoughts about the future.
• This version is closer to my original draft, with some updates for this occasion, plus an astounding $2^5$ added footnotes.