If you’re interested in game design, you should know Raph Koster. Full stop.
Koster made his reputation working on Ultima Online and augmented it through his work on Star Wars Galaxies (where he worked as Chief Creative Officer). To my mind, though, some of his greatest contributions come via his writing on games and game theory. His deceptively simple A Theory of Fun remains, IMO, one of the best ways to introduce game design to neophytes. But on his personal web site, he has written over a quarter-million words, most of it devoted to elucidating some large or small idea about game design. It’s accessible to non-specialists, well-written (he double-majored in Creative Writing and Spanish, the second of which must have taught him excellent grammar!) , and smart without being precious. Most importantly, it’s content-rich. I could imagine using his blog to supply many readings for a graduate class on game design.
Koster’s done would-be game designers a service by selecting some of his best posts on game theory and design and collecting them under a single heading, which you can access by clicking the link below: