On: Building the First GUIs

[mixmastamyk]

There were the original Apple and Gnome HIG (human interface guides). Also Ask Tog, and nngroup.com for web stuff.

[int_19h → mixmastamyk]

Windows also had one.

And they are all ultimately derived from IBM CUA, so that's a good start: https://en.wikipedia.org/wiki/IBM_Common_User_Access

[mixmastamyk → int_19h]

The classic Mac interface is a couple of years older, although most of these seminal works were published in the late 80s.