Though the presence of both science and technology in his fiction is often considerable, Thomas Pynchon is rarely classified as a science fiction writer. This may prompt consideration of both the nature of his writing and workable definitions of the genre. There are certainly examples and elements of science fiction in his work, ranging from “Minstrel Island” (1958), his unpublished co-authored musical, to Against the Day (2006), with its time machine theme. Yet there are also Pynchon texts – among them several early short stories collected in Slow Learner (1984) and his latest novel, Inherent Vice (2009) – which scarcely concern themselves with science or technology at all, either as overall themes or as props. Such fictions may appear as exceptions to a body of work almost defined by its preoccupation with the parameters and paraphernalia of science and technology: from the way it relates to and defines the very nature of power structures, industrialization or capitalism to its occasional, seemingly self-indulgent, nerdish romps around the material and technical details of some imagined gadget or piece of electronic equipment or machinery. As this Companion shows, however, applying a label such as “science fiction” would be reductive when trying to describe the many layers, strategies and effects of Pynchon's writing. Instead, this chapter explores a variety of the ways in which science and technology appear, and suggests a few overall strategies useful in the interpretation of Pynchon's fiction.