Heh. I have boxes of zines. At this point, I've been in slash fandom for 30 years (longer for general fandom) so have actually spent more time pre-Internet. And prior to the Internet, if you wanted fic, the only way to really get it was in zine form (fanzine, letterzine).
Actually, they are still being produced today. A number of media fandoms especially publish new fic in zine form first and only post to the internet after a year. They are a nice piece of history, but are really no different from the book your friend sent you to get you interested in slash.