1987 was the year that the Macintosh II, Apple’s first Macintosh to be released with a color display (supporting a spectrum of 256 colors), was released. It was also the year Apple published their Human Interface Guidelines.
What a treasure; I really need to grab a copy of this original HIG. I enjoyed Bryant's brief recap of some relevant quotes, but most importantly the emphasis on how little has changed over the last 30 years with regard to core user experience principles.
Reading the HIG front-to-back just once was really useful for me. Same for the Material spec. After having a foundation, it makes designing for each platform much faster because I have a better sense of where to go looking for answers.