The Game of the Book

Video Games are a medium that can easily be adapted from a book or comic series. Typically, to gain a mainstream audience a book is adapted into a movie. A less common occurrence is when a book is adapted straight into a game. These were common in the late 1980s and early 1990s when graphical computer games were becoming popular.

Typically, this comes in one of two ways:
 * 1) The book is adapted into a game without any intervening films.
 * 2) The game is released alongside a film, but as its own separate adaptation from it.

Type 1:

 * Tom Clancy is the Trope Codifier for this, with the Rainbow Six, Ghost Recon and Splinter Cell series. Tom Clancy examples go all the way back to the Red Storm Rising late-1980s sub sim.
 * Telltale Games' Bone and Sam and Max Freelance Police games.
 * The Discworld books have had a few games based on them: a Text Adventure based on The Colour of Magic, two Rincewind-centric games that took elements from multiple books, and Discworld Noir, which had an original protagonist and storyline. (There still haven't been any big-screen films yet, just TV movies.)
 * Infocom's adaptations of The Hitchhiker's Guide to the Galaxy and Shogun
 * Two for The Great Gatsby (not entirely serious).
 * I Have No Mouth, and I Must Scream
 * American Mcgees Grimm and Alice games take liberties with the source material, but are essentially Grimmified adaptations of books rather than any of the films based on the original written material.
 * A few comic-book games have adapted specific stories rather than general material or movie and TV versions of the characters or series:
 * Asterix has been adapted into several games on several platforms.
 * The Superman SNES and Genesis games adapting the "Death and Return" arc from the comics.
 * Ultimate Spider-Man, which was supposed to be in-continuity with a current arc of the comic. It didn't quite work out.
 * Marvel Ultimate Alliance 2 is a loose adaptation of the Civil War Crisis Crossover.
 * Years before that, Captain America (comics) and the Avengers was an even looser adaptation of the "Acts of Vengeance" crossover.
 * The Iron Man/X-O Man of War game adapts the intercompany crossover of the same title.
 * Hulk: Destruction got a Recursive Adaptation comics miniseries released simultaneously with the video game, creating an ambivalent example. Like the Ultimate Spider-Man example, it was supposed to be comic-book canon but didn't end up fitting properly.
 * The Ur Example comes from Tellarium Games in the early 1980s. They adapted several books into games with varying degrees of success from In Name Only (Swiss Family Robinson) to canonical sequels to the author's original work. The most famous of these was their Canon sequel to the Green-Sky Trilogy, which got the greenlight from Zilpha Keatley Snyder provided they use the game to reverse a decision she regretted making in the final book.
 * Ray Bradbury also helped write a Farenheit 451 gane for them that acts as a sequel to the book.
 * In 2010, Dantes Inferno was produced as an action-adventure game. The weird part is that the tie-in novel... was the actual 700-year-old epic poem, just with branding and art from the game.
 * The game Megami Tensei was born from a novel series, Digital Devil Story, that would become a large series containing plenty of spin-offs, such as Persona, and later games with the original name.
 * The official website for The Inheritance Trilogy has an Interactive Fiction game, Alagaesia Adventure Game. Considering that it's featured on the official site, it's probably at least a semi-official adaptation.
 * Companions of Xanth, a 1993 adventure game based on one of the Xanth books. Fittingly enough, the book in question is about someone playing a computer game that allows them to explore Xanth.
 * One of Interplay's early games was an Adventure Game based on Neuromancer.
 * Callahans Crosstime Saloon was also adapted (by Sierra) into an Adventure Game.
 * Metro 2033 is based on a Russian novel of the same name.
 * Earthbound 64, which later became Mother 3, had characters inspired by The Notebook
 * Suikoden was based off of The Water Margin.
 * Parasite Eve was the sequel to a novel.

Type 2:

 * Scott Pilgrim vs. The World: The Game is based on the comics rather than the movie, but the game and comic book were released in tandem.
 * Various Harry Potter games.
 * The Tick (animation) game was primarily based on the Animated Series, but also used several characters exclusive to the comics, such as the Running Man, the Red Scare and Clark Oppenheimer.

Both types:

 * The Lord of the Rings had both Type 1 and Type 2.