Just finished 22 immutable laws of marketing. Published in 1993 but still totally relevant (genuinely "immutable"). So many marketing books get out of date in a year or two. I strongly recommend this over any growth hacking blog from 2017.
"The Elements of Style" by Strunk and EB White is a fantastic book on writing from 1959,
A must-read if you find yourself producing any long format content!
For marketing, "Positioning" (also by Al Ries) was published in 1980 and is completely relevant. It's one of the must-read books on marketing.
I enjoyed "Calculus Made Easy" by Silvanus P. Thompson. It was published in 1910. The title is a bit unfortunate. It belies the great content within. I'd say I learned more about calculus from the first few chapters than I did from a semester at school.
"How to read a book" - Mortimer Adler
Its not an easy read but essential for everyone that reads a lot and wants to get the most out of it. 🤷♂️