Patchwork Story

This is a relatively long work which started its life as a bunch of shorter works in the same continuity, which were then edited together to form a single more-or-less coherent narrative. Sometimes this occurs through the addition of a Framing Device or Encyclopedia Exposita to tie the different narrative threads together; sometimes it just means the stories themselves are edited to increase continuity and remove redundant exposition; sometimes they are just put in chronological order.

This is very common in literary science fiction, especially from The Fifties and The Sixties when there was a shift in the genre from publishing in short-story-dominated magazines to publishing novels. In those circles it's generally referred to as a "fix-up", a name coined by science fiction writer A. E. van Vogt.

Compare Adaptation Expansion, Arc Welding, Clip Show, Compilation Rerelease, and especially Compilation Movie.

Literature
"The Ainulindalë and Valaquenta, which are given at the beginning, are indeed closely associated with The Silmarillion, but the Akallabêth and Of the Rings of Power, which appear at the end, are (it must be emphasised) wholly separate and independent. They are included according to my father's explicit intention; and by their inclusion the entire history is set forth from the Music of the Ainur in which the world began to the passing of the Ringbearers from the Havens of Mithlond at the end of the Third Age."
 * Most if not all of James White's Sector General books are stitched together out of short stories.
 * Several of Isaac Asimov's most famous books, including the first three Foundation books as well as I, Robot.
 * Borders of Infinity by Lois McMaster Bujold, which adds a framing narration.
 * Accelerando by Charles Stross started out as nine short stories.
 * Pretty much every Wild Cards novel.
 * Ray Bradbury's The Martian Chronicles.
 * Bradbury's The Illustrated Man is a number of short stories with a Framing Device about the titular Illustrated Man. All the stories are seen in his tattoos.
 * Stephen King's The Dark Tower was originally published as a series of short stories/novellas (hence its more episodic nature compared to the rest of the Dark Tower series).
 * The book Berserker is a collection of Fred Saberhagen's "Berserker" short stories linked together by narration by the Third Historian of the Carmpan (alien) race.
 * Larry Niven's "novels" Flatlander and Crashlander are actually his Gil "The Arm" Hamilton stories and Beowulf Schaeffer stories (respectively) collected together and given an external story to fit into.
 * The Big Four by Agatha Christie was originally a series of short stories that were published in The Sketch before being converted into a novel.
 * A Canticle for Leibowitz was originally three short stories: "A Canticle for Leibowitz", "And the Light Is Risen", and "The Last Canticle". The novel version is extensively edited, even changing the names of some of the characters.
 * Dune is an expanded and reworked version of two shorter works, Dune World and The Prophet of Dune, that were originally published in Analog magazine.
 * The Ship Who Sang by Anne McCaffrey.
 * The first Riverworld novel, To Your Scattered Bodies Go, was originally two novellas, "The Day of the Great Shout" and "The Suicide Express".
 * The Silmarillion wasn't even compiled together into its current relatively cohesive form by J.R.R. Tolkien himself, but rather by his son Christopher. To quote the latter's foreword:


 * Michael Swanwick's The Dragons of Babel.
 * Clifford D. Simak's City.
 * Orson Scott Card's EnderVerse Ender in Exile stitches together several pre-existing short stories with some new story and narrative. Important characters from the beginning and end of the book are not present in the end and beginning at all.
 * Tuf Voyaging
 * A.E. van Vogt's own The Voyage of the Space Beagle.

Tabletop RPG

 * Dungeons and Dragons. Four RPGA modules (R1 To the Aid of Falx, R2 The Investigation of Hydell, R3 The Egg of The Phoenix and R4 Doc's Island) were edited together to create I12 Egg of The Phoenix.

Video Games

 * Ys Book I & II for the Turbo Grafx 16 didn't merely slap Ys I and Ys II onto a single CD, but merged them together into one double-length game.