I think the general assumption is that there is no underground any longer as everything is online. But I still discover stuff that fly under the radar. Like this fanzine: Biblio-Curiosa published by a guy in Australia called Chris Mikul. I stumbled over an interview with him, but although he's interviewed online, and although I've found a few reviews of his zine, he has no webpage, no web shop, and no videos on youtube (that I know of anyway). His zine sounds great, though. And as I'm typing this I've just written to him and ordered a couple of issues (despite not having a website or a shop he does have an email address!).The interview was done by David Kerekes of Headpress fame. You'll find it right here. Headpress has published a couple of books based on Chris Mikul's other zine, Bizarrism (which I haven't seen either). And I think they might have something else he's written - I haven't looked too closely into it yet.
PS: I just got a reply from him. I asked him about his fb account (which I found). He says he logs in about once a year!
