>There's so much specialized knowledge out there, but often you'll only learn about it from someone else, or a highly technical book.
I remember my mind being blown by the Cal engineering library. Endless stacks and stacks of dense foundational knowledge from the 1950s-1990s you would never find on Google. Books are massively underrated these days.
Many large academic libraries have extensive digitisation efforts, though the results more often turn up on Hathi Trust (something of a waste of electrons in my view) than anywhere truly useful.
Hathi Trust itself grew out of Google's book-scanning initiative, and is shaped (and scarred) by copyright lawsuits.
That said, I hope some number of those works also find their way to Libgen and ZLibrary.
