Most of them are already quite old, I think the average age must be above 5 years, but I don' think they have lost their relevance. If you think they have, you may just be overestimating the speed of progress in IT. :)
Some of them have disappeared, or may disappear some time in the future. But I'm prepared, if that happens (or rather, when that happens), I'm replacing the link to the original site, by a local copy.
I am not pretending I wrote these articles. I didn't. But they were really important to me at the time, and I think it'd be really a shame if they just dropped off the net and disappeared forever. So, I'm trying to prevent that.
Welcome to the museum.
The copyright of these articles still lies with the original authors. As far as I'm concerned, it'll always be this way.
Mark Jason Dominus' 3 articles on why it's very unwise to use symbolic references (a variable holding the name of another variable).
This article has been distributed via CPAN, but it has been removed because of its old age. That's too bad, because it's really not outdated at all, in my opinion. It has been away from perl.com too, for some time — probably for the same reason; but now it's back.
Another of Tom Christiansen's classic articles, this one descibes why sub protoypes in perl aren't what one might hope they would be, and why, in general, you better stay away from them.
This article has been on CPAN and on perl.com too, but it has been removed, and hasn't come back — yet.
5sigma.com AKA Joseph N. Hall's illustrated tutorial on how the Schwartzian Transform works.
Reconstructed from the Wayback Machine.
An illustrated tutorial, aimed at Windows programmers, on how fork() works on Unix, and how the fork() emulation in Perl for Win32, 5.6 and higher, works.
Restored from the Wayback Machine — the original URL was http://www.geeksalad.org/odds/fork/all.shtml