A Programming Language (1962) [pdf]
softwarepreservation.org
softwarepreservation.org
because it pokes hard at OOP culture.
Some users thought his compiler was a farce before he posted the stats. Yea it's just a few pages, but the magic is getting to just a few pages. It apparently took 4M loc of added and then deleted code to get there (iirc it was a huge number).
It integrates an APL-like language (q) with a very nice time-series database (kdb+). Q programmers are highly prized on Wall St and can pull in truly staggering salaries.
Now i can relive the arguments about whether Sharp, STSC or APL2 was best
The language "A" was created to replace APL.
[0] https://en.wikipedia.org/wiki/APL_(programming_language)
If it was free I'd probably be using it.