A book written in 1910 could teach you calculus better than books of today (twitter.com)

yeah except now try change of variables. that's where ppl get in trouble

This is true of a lot of subjects. The old books and videos are better.

I find it useful, when I learn about something , to go to the origin of the thing I'm learning. For example, I want to learn about x86 assembly language and processor. Then I read first ever manual on x86. and manuals from processors that preceded it.