\startitem Even an old manual can quite well describe
functionality as much didn't change. It's only with \MKIV\ that
some compatibility is dropped and only for obscure features. Of
course I could trick users by regenerating a manual with a newer
date. I often use the excellent book \quote {\TEX\ by Topic} which
is already quite old and does not cover \ETEX, \PDFTEX, \LUATEX\
or whatever but what is told in it is still true. I never look at
it thinking it being old. \stopitem

Hans,

thanks for the compliments.

Let me point out that the source of TeX by Topic is available under the Gnu Public Documentation License, so anyone should feel free to add modern TeX additions to it. Personally I feel that the eTeX & pdTeX additions are mature enough that they could be added, of course with suitable markers to indicate their non-standardness. I don't have the time for this, but I'd welcome a collaboration with anyone that wants to invest the time.

Victor.