The encyclopedic novel is a literary concept popularised by Edward Mendelson in two 1976 essays ("Encyclopedic Narrative" and "Gravity's Encyclopedia"). In Mendelson's formulation, encyclopedic novels "attempt to render the full range of knowledge and beliefs of a national culture, while identifying the ideological perspectives from which that culture shapes and interprets its knowledge". In more general terms, the encyclopedic novel is a long, complex work of fiction that incorporates extensive information (which is sometimes fictional itself), often from specialized disciplines of science and the humanities. Mendelson's essays examine the encyclopedic tendency in the history of literature, considering the Divine Comedy, Don Quixote, Faust, Moby-Dick, and War and Peace, with an emphasis on the modern Ulysses and Gravity's Rainbow. Commonly cited examples of encyclopedic novels in the postmodern period include, in addition to Pynchon, Richard Powers' The Gold Bug Variations (1991), David Foster Wallace's Infinite Jest (1996), and Don DeLillo's Underworld (1997). Other literary critics have explored the concept since, attempting to understand the function and effect of "encyclopedic" narratives, and coining the related terms systems novel and maximalist novel. Mendelson describes numerous qualities of the encyclopedic novel: they include "the full account of at least one technology or science" and the display of "an encyclopedia of literary styles, ranging from the most primitive and anonymous levels ... to the most esoteric of high styles". He notes that there is often a short but significant interval between the era portrayed in the novel and the era of the novel's writing (as in, for example, James Joyce's Ulysses, and Thomas Pynchon's Gravity's Rainbow). Mendelson states that "[b]ecause they are the products of an epic in which the world's knowledge is larger than any one person can encompass, they necessarily make extensive use of synecdoche". Orderly plot structures are often absent.