PS, they didn't stop writing books with the advent of the internet. They don't have to contain out-of-date information, its not like there isn't out of date information on the internet...
and I'll add "Don't forget the GIGO law w.r.t. to anything computer related"
Trev. (a youngish 61)
Still running Raspbian Jessie or Stretch on some older Pi's (an A, B1, 2xB2, B+, P2B, 3xP0, P0W, 2xP3A+, P3B+, P3B, B+, and a A+) but Buster on the P4B's. See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm