What are your "required readings" for a game designers, that are not design books.

For instance, I think any systemic designer benefits from knowing the rules of DnD and MtG, including how they evolved and (most importantly) why.

@tomgrochowiak for realistic games - historical and sociological topics. I always find it sad when people design games where art is heavily grounded in reality and then game systems totally ignore that reality. i.e. the world looks "as if" but doesn't even attempt to mimic behavior as well when it comes to mechanics, NPCs, narrative, etc.
@tomgrochowiak I found "the humane interface design" and to be very insightful, and the book on impro theater by Keith Johnstone. Also any books on good writing.
@JohannaMakesGames There's also the ever-classic "The Design of Everyday Things" by Don Norman.
@tomgrochowiak The only work I would truly consider required reading for game design is The Designer's Heart Laid Bare. It's a short essay but it literally changed my life for the better as a designer and player of games.

@tomgrochowiak "The Animator's Survival Kit" and ideally also "The Illusion of Life", the two bibles of animation... because (too often forgotten) it is *essential* for designers to understand visual communication and how movement works, especially if they work at all on player movement or NPC behaviour, or anything visual or feel-related.

If you want the long(ish) version of why and how, read this: https://www.gamedeveloper.com/design/why-designers-should-learn-animation

Why designers should learn animation

Exploring why it is useful for designers to understand character animation, and where to start.

Game Developer
@tomgrochowiak Other interesting books in that direction include "Acting for Animators" (Hooks), "Peoplewatching" (Morris) and "Impro : Improvisation and the Theatre" (Johnstone).
@tomgrochowiak im currently reading the "patriarchy of things" and its phenomenal good. it explains how everything in the world is normed to male experiences .... very important for designers, imo