What matters in understanding digital media? Is looking at the external appearanceand audience experience of software enough—or should we look further? In ExpressiveProcessing, Noah Wardrip-Fruin argues that understanding what goes on beneath the surface,the computational processes that make digital media function, is essential. Wardrip-Fruin looks at "expressive processing" by examining specificworks of digital media ranging from the simulated therapist Eliza to the complexcity-planning game SimCity . Digital media, he contends, offer particularlyintelligible examples of things we need to understand about software in general; if we understand,for instance, the capabilities and histories of artificial intelligence techniques in the context ofa computer game, we can use that understanding to judge the use of similar techniques in suchhigher-stakes social contexts as surveillance.