The Beast Within: A Gabriel Knight Mystery (also known as Gabriel Knight 2: The Beast Within) is an interactive movie point-and-click adventure game, developed and published by Sierra On-Line for MS-DOS, Macintosh, and Microsoft Windows, and released in 1995. The live-action scenes star the talents of Dean Erickson and Joanne Takahashi in the game's lead roles. The sequel to 1993's Gabriel Knight: Sins of the Fathers and the second entry in the Gabriel Knight series, the game focuses on the lives of Gabriel Knight, an author who is descended from a family that combats supernatural evils, and Grace Nakimura, a student who assists Gabriel, as they become involved in a new case within Germany that focuses around a werewolf that has begun killing people around the city of Munich, and has connections to the lives of two famous people of Germany's history.
 Unlike its predecessor, the game was produced entirely in full-motion video – a technology that was popular at the time for game production but expensive to use. The game's story not only incorporates the mythology of werewolves and the rich history of Bavaria in its plot, but also improved on gameplay, including the involvement of a second playable character for exploration of the story in their perspective. Production on the game included recasting the roles of the main characters, due to the actors that voiced them in the previous title being unsuitable to portray them, and using computer-generated scenery for the location in the game, with filming minimized to two takes, and voice-over recording constrained to a single day due to the production budget.
 The Beast Within garnered critical praise for its storytelling and characterization, and has made appearances in numerous "best" lists, but was not a commercial success following its release. Despite this, it spawned a sequel, Gabriel Knight 3: Blood of the Sacred, Blood of the Damned, in 1999.
 The Beast Within is a point-and-click adventure game, played from a third-person perspective; a first-person perspective is used at some points during the game. The story is divided into six chapters that plays out in a linear fashion, all of which is conducted between the two playable characters – half involve Gabriel, and the other half involve Grace. In each chapter, players must complete a set of required actions in order to advance the story, but may do so in a non-linear fashion, and can conduct optional actions that can provide background on the game's story and events. Each chapter features a variety of locations that the player can visit, some of which involve an overhead map which uses a hint system to highlight key locations that have actions to be performed in the chapter. With Sierra games of the time,  a running score is used to keep check on actions, both required and optional, that players have completed (i.e. acquiring an object needed for a puzzle).
 In each location, the player can move the cursor to find items to interact with, or places where they can move to another spot or site. Unlike Gabriel Knight: Sins of the Fathers, the cursor is context sensitive, and will conduct an action when the player interacts with something, depending on what the interaction will involve - interacting with a person, for example, will begin a conversation. However, items collected and placed in the character's inventory, which can be examined when selected, need to be made an active item before they can be used on interactive objects. Other options include: access to a main menu to save/load a game, change settings, or quit the current game; a movie section, allowing players to replay movies unlocked during the game; and an option, available until the final chapter, to look back over previous conversations as Gabriel, or review notes made by Grace. Conversations focus on a series of topics, with additional ones becoming available as the player makes progress on the story. In some situations, the player must overcome a dangerous situation or risk occurring a game over moment, forcing them to retry, restart the game, or restore a previous save.
 The Beast Within takes place within a world where supernatural forces, both good and evil, have existed throughout human history, with any becoming a threat to humanity being combatted by people who specialize in fighting such powers. The story incorporates the mythology of werewolves, and the historical backgrounds of King Ludwig II and Richard Wagner between 1870 and 1886, as well as fictional events surrounding the relationship between the two during this period of Germany's history. Locations used in the game include the city of Munich, the fictional town of Rittersberg, and a number of sites around southern Bavaria, including Neuschwanstein Castle.
 Novelist Gabriel Knight has taken over residency of his Ritter family's ancestral castle Schloss Ritter in Rittersberg, Germany, after writing a bestseller novel entitled The Voodoo Murders based on his experiences from the previous year in New Orleans (Sins of the Fathers). While seeking inspiration for a new manuscript, Gabriel is still adjusting to his new responsibilities as the latest Schattenjäger ("shadow hunter") – a role his ancestors have assumed in combatting supernatural evils. One night, the local citizens ask Gabriel to investigate a mysterious death they believe was caused by a werewolf. Gabriel asks Gerde Hull, caretaker of Schloss Ritter, to do research on the matter while he investigates the crime scene in Munich.
 In Munich, Gabriel learns of recent killings that the press and local police believe may be committed by escaped zoo wolves. Gabriel's evidence however points to a wolf-like but different, larger animal as the culprit. His investigation leads him to an exclusive hunting club; its leader Baron Friedrich Von Glower, intrigued by Gabriel and noting he comes from an admirable German bloodline, welcomes him as a member.
 Meanwhile, Gabriel's assistant Grace Nakimura, left to tend his bookshop in New Orleans, flies to Rittersberg upon receiving word from him about his new case. She becomes annoyed when she can't track Gabriel down and Gerde will not volunteer his whereabouts. After mistakenly concluding that Gerde and Gabriel have a romantic relationship, she grows angry and insists she take over research duties. Grace later realizes her mistake and apologizes for her behavior. Grace discovers information about the Black Wolf, a werewolf who terrorized the area centuries before, and a connection to King Ludwig II of Bavaria. She sends her findings to Gabriel via his family lawyer.
 In Munich, Gabriel is annoyed Grace has come to Germany, believing this case is too dangerous. To keep her at safe distance, he suggests she investigate Ludwig's connection. Gabriel learns that the hunting club has a philosophy that humanity has become complacent and should revitalize lost animal instincts, often through hunting and hedonism. While Gabriel comes to suspect club member Von Zell, he also develops a friendship with Von Glower.
 Grace visits museums including King Ludwig II's Neuschwanstein Castle, gains access to his diary and discovers that Ludwig II suffered from lycanthropy thanks to the Black Wolf. Ludwig and Richard Wagner made experiments together to produce a sound combination to force a werewolf's transformation, written in an opera by Wagner. But their plan to expose and kill the Black Wolf with the opera were halted by Wagner's death, and Ludwig hid the score sheets before being arrested on grounds of insanity, leaving the opera lost.
 Gabriel partakes as the hunting club goes on a hunting trip, and he discovers proof of Von Zell being a werewolf: Gabriel witnesses him eating human remains in a hideout in the forest. Gabriel reveals this to Von Glower, who, horrified of what he learns, agrees to help kill him. Gabriel is bitten by the werewolf before Von Glower arrives and, hesitant to shoot, throws Gabriel his rifle. Gabriel kills the wolf before passing out, now infected with lycanthropy. Grace arrives in Munich and finds Gabriel, who is put into quarantine.
 Grace and Gabriel learn Von Glower is the hundreds-years-old Black Wolf; as the source of the curse he is the "alpha" whom Gabriel must kill to cure himself. In a letter, Von Glower discloses he infected Von Zell (who then lost his sanity) as a failed attempt to gain a companion, and pleads to Gabriel as a kindred spirit, asking that he embrace lycanthropy and join him as a werewolf. Grace finds the score to Wagner's lost opera, and a great performance is arranged. The opera is performed with Von Glower in the audience, and at the opera's climax Von Glower and Gabriel both turn into wolves. They run to the opera house's basement where Grace and Gabriel force Von Glower into an incinerator, burning him alive. With his death, Gabriel's lycanthropy is cured. Afterward, Gabriel mourns Von Glower, admiring the man despite his actions. He then assures Grace that he will no longer keep her at a distance during dangerous cases.
 The game was released for PC and Macintosh. The Macintosh version uses a video player developed by Sierra instead of an off-the-shelf technology such as QuickTime, and had a tendency to crash or run slowly on 680x0 processors. There is an XP-compatible re-print on DVD with de-interlaced movies, but it is exclusive to the Italian market.
 The Beast Within has a much more involved plot than its predecessor, Sins of the Fathers. Jane Jensen said that this was because the FMV graphics "limited the interactivity we could do. I specifically tried to put a lot more intrigue in the plot, so even though the interactivity was easier, there would still be enough meat going on to keep people engaged".
 The role of Gabriel Knight was re-cast, since Jensen felt Tim Curry, who voiced Knight in Sins of the Fathers, did not look the part. Dean Erickson took the part, and delivered a take on the character markedly different from Curry's. Erickson explained that "there was no way I was going to do Tim Curry, because... you know, Tim Curry is Tim Curry. He was a little more animated or maybe you could say over the top. What he was doing called for that. What I was doing called for something a little more down to earth and grounded". He clarified that "[Curry] only voiced a character and, due to the nature of animation, voices often need to be more over-the-top, because they have to impart more of everything without the visual aspect of a real, live person on screen".
 To prepare for the role, Erickson intensely studied films with Southern characters and voice tapes of Southern dialects in order to make his accent sound natural. He enjoyed the role and later said that if the Gabriel Knight series had continued using live action FMV, he would have done more.
 Filming for the cut scenes was done in California during mid-1995. Erickson recalled that due to video game budget constraints, the actors were expected to show up at the set prepared to give a perfect delivery; director Will Binder would not run more than two takes of any scene unless absolutely necessary. In addition, all of Erickson's narrative voice overs were recorded in a single day at a sound studio.
 According to Jensen, The Beast Within badly ran over its "original modest... budget". She summarized:
 "Let's just say that the struggles between budget and schedule vs. production standards vs. story and content were about as bad on GK2 as I've ever experienced, not just for three months or so, but for the entire production phase, about 18 months. For 18 months I had the Sword of Damocles - that ultimate designer threat of either cancellation or serious cuts and restructuring hanging over my head". In Neuschwanstein, the actual paintings in the Singer's Hall were changed to correspond with the plot. The filming for the cut scenes was partly documented in the British series Bad Influence!, leading to presenter Violet Berlin having a brief walk-on cameo.
 According to Todd Vaughn of PC Gamer US, the original Gabriel Knight was not as successful as Jensen had wanted. However, he noted before The Beast Within's release that "she's hoping the same attention to character development and puzzles, coupled with the new video technology, will satisfy both the hard-core puzzler and reach a broader audience".
 In every Gabriel Knight game, the popular gospel hymn "When the Saints Go Marching In" can be heard, albeit in different remixes and forms. In The Beast Within it is heard when Gabriel is visiting the Marienplatz in Munich.
 As well as creating the soundtrack for the second game alongside Jay Usher, series composer Robert Holmes wrote the music for a scene from the fictional opera entitled "Der Fluch Des Engelhart" ("The Curse of Engelhart").
 In the United States, The Beast Within was the fourth-best-selling computer game of January 1996, and the 17th-best-selling of the first six months of 1996. The game and its predecessor, Gabriel Knight: Sins of the Fathers, sold a combined total of 300,000 copies by December 1998. Leslie Gornstein of the Orange County Register wrote that these numbers were "considered a success in the world of adventures, according to Jensen". Elsewhere, Jensen expressed frustration with The Beast Within's commercial performance. She wrote that she had expected it to appeal to a large, mainstream audience, and remarked in retrospect, "I thought it would be top ten. And it was - for about a week". Jensen further commented that the game's Christmas Eve launch was a contributing factor to its underperformance.
 The game was very well received by critics; at GameRankings it scores 90.50% (based on 6 reviews). William R. Trotter of PC Gamer US wrote that "The Beast Within sets a new standard — within the graphic adventure genre, at any rate — for interactive entertainment". In Computer Gaming World, Johnny L. Wilson similarly declared it "a graphic adventure benchmark".
 Critic Philip Jong of Adventure Classic Gaming gave the game 5 out of 5 stars, saying that it "is an epic interactive adventure that triumphs in both gameplay and storytelling. It masterfully blends fantasy and a touch of real life history to add an unparalleled degree of realism to an adventure game. With this title, Sierra On-Line sets the standards for developing strong female leading roles; Jensen should be praised for her development of an intelligent female role model". A Next Generation critic likewise praised the character of Grace, as well as Joanne Takahashi's "appropriately sardonic" performance in the role. He compared the game favorably to Sierra's Phantasmagoria (which uses the same engine), citing the greater amount of gameplay content and better scenery, and rated it one of the overall best graphic adventures due to its "detailed and evolved storyline with an easy to use yet sophisticated graphic system". Maximum commented that "The Beast Within is one of the few [interactive movies] which manage to grasp the attention of the player, largely due to the interesting plot that runs throughout. Graphically the game is pretty smart too, the digitised actors working well with the computer-generated [scenery] on which they're super-imposed".
 The Beast Within won Computer Gaming World's 1995 "Game of the Year" award, and was named the best computer adventure game of 1995 by Computer Games Strategy Plus, and the best of 1996 by GameSpot and PC Gamer US. It also won GameSpot's "Best Story" prize. Hailing it as "one of the best adventure games ever", the editors of PC Gamer US wrote: "If it had been just a movie, The Beast Within would easily beat 99 percent of what passes for horror on the big screen these days". The staff of Computer Gaming World called it "the continuation of a brilliant tradition—the graphic adventure as art".
 The Beast Within was a finalist for the Computer Game Developers Conference's 1996 "Best Adventure Game/RPG", "Best Script, Story or Interactive Writing" and "Best Use of Video" Spotlight Awards. However, these prizes went respectively to The Elder Scrolls II: Daggerfall, You Don't Know Jack XL and Wing Commander IV. In 1996, GamesMaster ranked the game 71st on their "Top 100 Games of All Time."
 In 1998, The Beast Within was adapted into a novel by Jane Jensen. The novel adaptation of the first game is a straightforward adaptation of the events of the game, an approach which Jane Jensen decided, in retrospect, was not the most successful way of introducing Gabriel Knight to a literary audience. For the second novel she "threw the whole idea of the game away and started again from scratch". Both books are out of print as of 2010. As part of her 2012 Kickstarter campaign to fund a new adventure game, Jensen offered both Gabriel Knight novels as ebooks to backers who pledge $50 or more.
 In 1996, Computer Gaming World named The Beast Within the 17th best computer game ever, the highest position for any graphic adventure. The editors declared Jane Jensen as "the interactive Anne Rice". In 1998, PC Gamer US declared it the 27th-best computer game ever released, and the editors wrote that it "edges out the first [game] in pure excitement and graphic splendor". In 2000, Computer Games Strategy Plus named The Beast Within one of the "10 Essential Graphic Adventures", and called it "probably the best video-based adventure game ever released". In 2011, Adventure Gamers named Gabriel Knight 2 the 3rd-best adventure game ever released.
 In a 2004 retrospective review, Adventure Gamers' Dan Ravipinto called The Beast Within "one of the few computer games to actually involve personal, meaningful growth in a player-character. Easily one of the best Full Motion Video games ever made".
 Writing for Vice Media in 2021, Jess Morrissette credits the game's writing, acting performances, and queer themes, calling The Beast Within a "minor masterpiece in adventure gaming".