The vast majority of computer science lectures from 20 years ago are still relevant. A ton has changed in terms of frameworks but the fundamentals are mostly the same.
Maybe I was in the wrong subsector of this industry but there was very little theory work in the jobs I have held. A lot of it was just reusing the same design patterns over and over again, and then scaling that out somehow.
I did not mean my comment to say that seminal works in CS theory are useless, just that most of the books published in this field cover more practical matters and they tend to age very quickly. Like I have an e-bookshelf full of Packt freebies back when they did that, and those books aren't really that useful now unless I want to start on an old version of something.
It is, but it isn't. Besides, from my vantage point almost all the work is herding frameworks of some kind. Maybe I need to get out of web tech and into something else.
One other point (since I can't edit): none of the used bookstores I am aware of take old technical books. Even the good ones (because they don't know and just see another tome that will likely sit on a shelf and collect dust)
