Systems novel is a literary genre named by Tom LeClair in his 1987 book In the Loop: Don DeLillo and the Systems Novel, and explored further in LeClair's 1989 book, The Art of Excess: Mastery in Contemporary American Fiction. LeClair used systems theory to critique novels by authors including Thomas Pynchon, William Gaddis and Ursula K. Le Guin. Citing Fritjof Capra's description of systems theory as a "new vision of reality", LeClair invoked ideas from thinkers such as James Lovelock, Gregory Bateson and Douglas Hofstadter to analyse how the novels in question depicted processes and relationships within social, cultural, economic and political systems. LeClair's systems novels were all "long, large and dense" and all in some way striving for "mastery", showing similarity to Moby-Dick and Absalom, Absalom! in "range of reference, artistic sophistication, and desire for profound effect."
Subsequent critics widened the geographical range but mostly adhered to the notion that systems novels were typically large and dense, making the concept overlap with other critical terms such as encyclopedic novel and maximalism. This weakened its usefulness as a genre definition, but with the rise of the internet, the systems novel has come to be seen as reflecting the conditions of network culture. The term is now used in at least two different ways, stemming from LeClair's thesis though with different emphases. One highlights bulk, broadness of scope, range of content and greatness of ambition. The other highlights engagement with scientific and technological concepts such as information theory, complexity and emergence. Some systems novels fit both categories, though not all.