Zen and the Art of the Internet
A 1992 beginner's guide to the internet, written by a student and given away over the very network it described.
Brendan Kehoe at Widener University wrote it as an introduction to email, anonymous FTP, Usenet, Telnet, finger and search tools such as Archie. It went out as freely downloadable text and PostScript and was copied to countless FTP archives before Prentice Hall published it as a book the same year. The web barely gets a mention — it existed, but hardly anyone was using it yet.
The guide taught a generation of newcomers not just the commands but the manners: read the FAQ before asking, and Usenet does not appreciate the same question posted to twenty groups. Today it is a time capsule of the internet in the last moment before it stopped being a university network.