The Star Trek franchise has produced a large number of novels, comic books, video games, and other materials, which are generally considered non-canon.
Continuity
Star Trek spin-off fiction frequently fills in "gaps" within the televised show, often making use of backstage information or popular fan belief. Although officially licensed spin-off material will often maintain continuity within itself (particularly within books by the same authors), elements often contradict each other irreconcilably. For example, the end of Kirk's five-year mission has been depicted in several different incompatible ways.
Much fiction is set in a second five-year mission of Kirk's Enterprise, which the Okuda chronology dates after Star Trek: The Motion Picture (although novels often placed it before). Backstories and fates of characters are often elaborated on, an example being Leonard McCoy's divorced status, and his daughter, Joanna, originally intended to appear in what became the TOS episode "The Way to Eden".
Several original series characters are established as still being alive in the TNG era, including McCoy, Spock, and Scotty. In the books written by William Shatner, these are joined by a revived Captain Kirk. Several novels depict the careers of the younger members of the Enterprise crew after Star Trek VI: The Undiscovered Country. Captain Sulu and his daughter Demora Sulu appear in Peter David's novel The Captain's Daughter. In the novel The Sundered, Chekov serves as Sulu's first officer on . The novel Federation has Chekov eventually becoming an admiral. Uhura is shown, in the novel Catalyst of Sorrows, to be Chief of Starfleet Intelligence in 2360. The 2006 novel Vulcan's Soul: Exiles has an Admiral Pavel Chekov, and Uhura is still serving as head of Starfleet Intelligence in 2377, at the age of 138. Peter David's novel Imzadi explores the backstory between Riker and Troi, and its sequel Triangle: Imzadi II covers the cooling of the Worf/Troi relationship, which was left unexplained on screen.
Spin-off fiction will often use re-use characters who appeared only once or twice in the actual show. Dr. Selar has appeared in more TNG novels than television episodes, and she and Elizabeth Shelby, who appeared in the two-part episode "The Best of Both Worlds" are major characters in the Star Trek: New Frontier series. The cast of the Starfleet Corps of Engineers series largely comes from such guest parts. Similarly, the IKS Gorkon series features Klingon characters drawn from a variety of TNG and DS9 episodes.
The spin-off fiction has also engaged in world building. Novels in the 1980s by Diane Duane and John M. Ford established a complex backstory and culture for the Romulans (Rihannsu) and Klingons respectively, which were later not taken up by TNG.
Technical and reference manuals
A large range of fictional reference books have been produced over the years. More recent books of this sort have been by production staff and, whilst not binding on the series, nonetheless reflect the thinking of the production office, and are used as sourcebooks by writers.
The Star Trek Star Fleet Technical Manual (Franz Joseph, 1975) Star Trek Spaceflight Chronology (Fred & Stan Goldstein, with Rick Sternbach, 1980) The Klingon Dictionary (Marc Okrand, 1985 (1st ed.), 1992 (2nd ed.)) Mr. Scott's Guide to the Enterprise (Shane Johnson, 1987) Star Trek: The Next Generation Technical Manual (Michael Okuda and Rick Sternbach, 1991) Star Trek Chronology (Michael & Denise Okuda, 1993, 1996) Star Trek Encyclopedia (Michael & Denise Okuda, Debbie Mirek, 1994, 1996, 1999) Star Trek: Deep Space Nine Technical Manual (Rick Sternbach, Herman Zimmerman, Doug Drexler, 1998) Star Trek Star Charts (Geoffrey Mandel, 2002)
Similar material has also been published in the Star Trek Fact Files and the Star Trek Magazine.
Prose fiction
Since 1967, hundreds of original novels, short stories, and television and movie adaptations have been published. The first original Star Trek novel to be published was Mission to Horatius by Mack Reynolds, which was published in hardcover by Whitman Books in 1968. Geared for younger readers, the novel became a collectible and in the 1990s, Pocket Books issued a facsimile edition.