"The History of Fortran I, II, and III" (1979) - because this historical piece by the author of the first high level language brings home the core principles of language design [https://archive.org/details/history-of-fortran]
If your are interested in learning hard subjects, I highly recommend Richard Hamming's wonderful course The Art of Doing Science and Engineering: Learning to Learn [1], and the related book [2]
"The Mythical Man Month" (1975) - because human nature hasn't changed [https://www.amazon.com/Mythical-Man-Month-Software-Engineeri...]
"The History of Fortran I, II, and III" (1979) - because this historical piece by the author of the first high level language brings home the core principles of language design [https://archive.org/details/history-of-fortran]
"The Unix Programming Environment" (1984) - because the core basics of the command line haven't changed [https://www.amazon.com/Unix-Programming-Environment-Prentice...]
"Reflections on Trusting Trust" (1984) - because the basic concepts of software security haven't changed [https://www.archive.ece.cmu.edu/~ganger/712.fall02/papers/p7...]
"The Rise of Worse is Better" (1991) - because many of the tradeoffs to be made when designing systems haven't changed [https://www.jwz.org/doc/worse-is-better.html]
"The Art of Doing Science and Engineering: Learning to learn" (1996) - because the core principles that drive innovation haven't changed [https://www.youtube.com/playlist?list=PL2FF649D0C4407B30] [https://www.amazon.com/Art-Doing-Science-Engineering-Learnin...]
"xv6" (an x86 version of Lion's Commentary, 1996) - because core OS concepts haven't changed [https://pdos.csail.mit.edu/6.828/2011/xv6/xv6-rev6.pdf] [https://pdos.csail.mit.edu/6.828/2014/xv6/book-rev8.pdf]