Understanding Computers and Cognition: A New Foundation for Design is another classic I should almost certainly have read ages ago. It gives very straigthforward explanations of why language and cognition are complex social processes and how this presents huge challenges for designers and for the whole field of AI.
I also enjoyed the wonderful predictions that by 1988 we would have “thinking computers” and advertisements from 1982 offering “programs that understand you so that you don’t have to understand them”. Technology progresses, hype remains a constant!
It is also interesting that “not having to understand” was promoted, rather than “being easy to understand”, even back then. I’ve always thought of usability about being helpful and increasing clarity, rather than about encouraging people not to think at all.