The Hitchhiker's Guide to the Galaxy (series)

The Hitchhiker's Guide to the Galaxy is a comedy science-fiction franchise, stretching through various media. It was created by Douglas Adams roughly contemporaneously with his work on Doctor Who, leading to a large number of in- and out-of-universe connections between the two series.

Premise
The series generally focuses on the haphazard journeys through the Galaxy of Arthur Dent, an ordinary man who becomes one of the only survivors of the human race after the Earth is destroyed for trivial reasons by Vogons. He becomes the companion of intergalactic hitchhiker Ford Prefect, with their party also joined by the eccentric, deserting President of the Galaxy Zaphod Beeblebrox, a superintelligent but depressed android called Marvin, and Trillian (formerly Tricia McMillan), the only other survivor of humanity. They become embroiled in a quest for "the Ultimate Question of Life, the Universe and Everything", with it being revealed that the Earth was not a naturally-occurring planet but was instead created by a race of pandimensional beings as an organic supercomputer to calculate the Question.

Notably, the various media under the Hitchhiker's Guide to the Galaxy umbrella are not straightforwardly in-continuity with one another. Instead, Adams, when bringing his characters to a new medium, invariably restarted Arthur's story from square one, freely altering details while taking inspiration from previous tellings.

Shared Douglas Adams universe
Douglas Adams served as script editor on Doctor Who television stories contemporarily to his writing of the original Hitchhiker's Guide to the Galaxy radio series and the first few Hitchhiker's novels.

In 1976, prior to creating The Hitchhiker's Guide to the Galaxy or getting official work on Doctor Who, Adams pitched The Krikkitmen to the Doctor Who production office. It would have introduced the titular Krikkitmen. It was rejected by Robert Holmes, although the story would ultimately resurface in 2018 as a novelisation by James Goss under the title of Doctor Who and the Krikkitmen.

The Pirate Planet, the first produced Doctor Who story written by Adams, debuted a few months after the radio series, airing between 30 September and 31 October 1978. It had the Fourth Doctor quote "Don't panic!", the tagline of the in-universe guidebook and a phrase frequently used by Ford Prefect, and introduced the planet Qualactin and the mineral Madranite. A year later, Destiny of the Daleks, broadcast in September 1979, had the Doctor prominently mention the planet Betelgeuse, the home of Ford Prefect. It also mentioned Oolon Colluphid as the author of a book about "the origins of the universe" which the Doctor found laughable; the opening of the radio series had mentioned him as the author of multiple sceptical theological books: Where God Went Wrong, Some More Of God's Greatest Mistakes, and Just Who Is This God Person, Anyway?.

A year after The Pirate Planet, and the month after Destiny of the Daleks debuted, the first of Adams's Hitchhiker's novels came out. Simply entitled The Hitchhiker's Guide to the Galaxy, it was an adaptation and expansion of the radio series' first four episodes, and came out on 12 October 1979. Qualactin and Madranite from The Pirate Planet were namedropped (and Oolon Colluphid was once again prominently referenced).

Adams also scripted Shada, a story intended to be released at the end of Season 17 in early 1980, although due to a BBC strike it remained unproduced in live-action form for decades. Adams's script involved a sofa being dematerialised into the Time Vortex. (In the filmed version, this was replaced with a tray for unknown reasons.) Around this time, Adams also made a second attempt to produce The Krikkitmen, this time hoping to make it a special one-off feature film. After this failed, Adams finally introduced the Krikkitmen in the third Hitchhiker's novel (and the first not to adapt existing episodes of the radio series),. Also in this book, Qualactin is once again name-dropped, and due to "eddies in the space-time continuum!", a sofa spontaneously rematerialises first on prehistoric Earth, then jumps forward — with Arthur Dent and Ford Prefect in tow — to the present day. Prefect recognises that the sofa must have been "washed up out of the continuum", calling it "space-time jetsam", and its origins are not otherwise addressed.

Shada also introduced Professor Chronotis, a character whom Adams would eventually return to in 1987's Dirk Gently's Holistic Detective Agency, the first in his Dirk Gently series. The Earthbound Dirk Gently books constituted a different series from The Hitchhiker's Guide to the Galaxy but also seemed to share a universe with them, in the same subtle way as Adams's Doctor Who and Hitchhiker's work: episode four of the Hitchhiker's radio series had featured a cameo by a group of Norse deities surviving into the modern day, described as "has-beens". These characters would prove essential in the second and final completed Dirk Gently novel,, whose title was, in addition, lifted from Life, the Universe, and Everything.

Subsequent in-universe connections
Other writers continued to indicate that Doctor Who and The Hitchhiker's Guide to the Galaxy both took place in a shared universe. As early as 1995, Managra and Lords of the Storm, two separate Missing Adventures, featured further references to the planet Betelgeuse. It would be mentioned by multiple other stories in the 21st century. In 2001, a few months before Adams's passing, Storm Warning, the first of Big Finish Productions' audios starring Paul McGann's Eighth Doctor, featured an Altairian dollar, a currency from the Hitchhiker's series.

In 2002, the six episodes of the 1981 TV miniseries version of The Hitchhiker's Guide to the Galaxy were released on DVD. On the second DVD disc, a Making Of… documentary was included. Its credits were animated and showed the Doctor's TARDIS tracking a space-ship upon which Arthur was getting a lift. The ship was actually the Liberator from Blake's 7, making this a three-way crossover between the three largely contemporary 1970s-1980s BBC sci-fi cult classics.

In 2003, the BBC released a webcast version of Shada starring Paul McGann's Doctor. A Nutri-Matic Drink Synthesizer (a technology introduced in Hitchhiker's) was visible in St Cedd's College, and Arthur Dent and Zaphod Beeblebrox themselves made cameos as inmates of the Shada prison itself.

The defictionalised Who is Doctor Who? website put online as part of the marketing campaign for Series 1 of Russell T Davies's revived Doctor Who TV series, included Have You Seen This Man?, a collection of flash fiction that told sightings of the Ninth Doctor. One of them was in-character from Arthur Dent, suggesting that the Doctor had briefly helped him hold off the bulldozers trying to raze his home, placing the encounter right before the beginning of the plot of The Hitchhiker's Guide to the Galaxy (which opens on a lone Dent's argument with the demolition workers). The Christmas Invasion, written by Davies himself and broadcast on 25 December 2005, had the newly-regenerated Tenth Doctor mention meeting Arthur Dent. This was elaborated in the later 2018 novelisation of The Christmas Invasion by Jenny T Colgan, which stated that Dent had unsuccessfully attempted to convince the Doctor to kill Vogons and that the Doctor had apparently been acquainted with Ford Prefect in "college".

In 2007, Davies also wrote Voyage of the Damned, a Tenth Doctor Christmas special primarily concerned with a spaceship named the Titanic in honour of the original Earth cruise liner. The Starship Titanic, which predictably met the same fate as its inspiration, was offhandedly mentioned in Life, the Universe, and Everything, the 1982 third novel in the Hitchhiker's series. Notably, in 1998, Adams had written, a video game elaborating on this idea and taking it in a different direction than Davies' version.

In 2008's Eighth Doctor audio story Max Warp, a spaceship was described as "a Lazlar Lyricon custom job". This descriptor was also applied one of the spaceships in the Milliways car park in Episode 5 of the original Hitchhiker's radio series.

In 2009's A Sting in the Tale, the Fourth Doctor mentioned the Vogons in a list of malevolent alien races who presented a threat to the Earth.

As highlighted on the Doctor Who website at the time in a promotional shot, among the books in the Library in Silence in the Library were the titular Hitchhiker's Guide to the Galaxy, filed next to Oolon Colluphid's Origins of the Universe and the operational handbook for a Type 40 TARDIS.

In the 2013 Second Doctor comic story Bazaar Adventures, the Doctor, Jamie McCrimmon and Zoe Heriot passed by a "Babel Fish Aquarium", the Babel fish being an alien animal species prominently featured throughout the Hitchhiker's franchise. Later, the television story The Rings of Akhaten showed the Eleventh Doctor, as he pointed out species in a crowd of aliens to Clara Oswald, mentioning the Hooloovoo, a species introduced in the first Hitchhiker's novel.

In 2017, a "completed" version of the Fourth Doctor Shada was released, incorporating all the 1980 live-action footage and completing it with newly-animated scenes based on the original script. The new segments snuck in original allusions to The Hitchhiker's Guide to the Galaxy: Chris Parsons's room contained two books entitled Zaphod: My Stories and Hyperspace Bypass Planning Law. The former appears to be an autobiography by Zaphod Beeblebrox, while a "hyperspace bypass" is what the Vogons destroyed the Earth to build.

In 2021, Big Finish released an audio adaptation of The Doomsday Contract, an unproduced story by Adams' friend John Lloyd. Big Finish also released a trailer titled Tom Baker stars in John Lloyd's lost Doctor Who adventure, The Doomsday Contract to promote the audio, styled as an homage to The Hitchhiker's Guide to the Galaxy TV series due to Adams' involvement in the story's production.

Cultural references
Although the majority of back-and-forth connections between Doctor Who and The Hitchhiker's Guide to the Galaxy acknowledged a shared universe, there were also cultural references to each franchise within the other on occasion, though never under Douglas Adams's pen.

As early as 1981, the short story A Midsummer's Nightmare in the Doctor Who Annual 1981 saw Romana II comment that she had chosen to attend a performance of the Hitchhiker's Guide to the Galaxy stage play over A Midsummer Night's Dream. She called it a comparatively "much more useful play, and much funnier too".

In Damaged Goods, a 1996 Virgin New Adventures novel notable as Russell T Davies's first official contribution to the Doctor Who series, Chris Cwej found "a twentieth-century paperback that used the phrase Mostly Harmless" in the TARDIS library. Cwej was depicted as unsure whether the book had been fiction or non-fiction.

In …And Another Thing (2009), the sixth official Hitchhiker's novel, written by Eoin Colfer with the authorisation of Adams's widow, Arthur Dent is said to be reminded of watching "the special effects of early Doctor Who" as he watches the Earth being destroyed from a porthole on the Heart of Gold.

In Gareth Roberts's novelisation of Shada published in 2012, it is mentioned that to disguise his theft of The Worshipful and Ancient Law of Gallifrey from the Panopticon Archive on Gallifrey, Professor Chronotis replaced it with a book heavily implied to be the original Hitchhiker's novel: Chronotis decribes it as "an Earth classic by one of the greatest writers in that planet's history". Chronotis then went on to say "... terribly funny, terribly thoughtful, wish I could remember the name of it, something about thumbing a lift, and there were towels in it ... oh yes, of course, it's called The Hitch—" before being interrupted. (PROSE: Shada)

Other references
Quotes and allusions were sometimes made to The Hitchhiker's Guide to the Galaxy in Doctor Who media or vice-versa in ways that would be recognisable to readers without necessarily being in-universe connections, whether they be implications of a shared universe or in-universe cultural references.

In, the second Hitchhiker's novel, a prominent plot point parodied The Ark in Space. One line explicitly referred to the book's colony ships as "three Arks in Space".

In Ghost Light, the Seventh Doctor once asked, rhetorically, who had said that "Earthmen rarely invite their ancestors to dinner", which came from the series. asked a near-identical question, albeit with different wording when attempting to recover his TARDIS alongside River Song on Cheska Minor in the audio story Animal Instinct.

In addition to the in-universe references documented above, the Eighth Doctor version of Shada specified that the car which Skagra steals into a Ford Prefect (and its owner the treasurer of the Ford Prefect Appreciation Society), which Gary Russell confirmed was intended as a further nod to the Hitchhiker's series.

In the short story Wish You Were Here, Lakksis used the phrase "Life, don't talk to me about life", often used by Marvin in the Hitchhiker's series.

The episode 42 shares its title with the "" in the Hitchhiker's series. As with the spaceship stolen by Arthur Dent and friends in The Restaurant at the End of the Universe, the ship in 42 is on its way to crashing into a star, leaving its passengers with no escape. The number 42 was later one of the numbers the Tenth Doctor guessed when trying to find out the security protocol for the Host in Voyage of the Damned.

Cast and crew connections
Because Paddy Kingsland did special sounds for both the Hitchhiker's Guide radio programme, and for The Sun Makers, there are sounds which are common to both productions. Notably, the sound of the Fourth Doctor fiddling with a combination lock in part 4 is the same as the sound heard in Hitchhiker's whenever the Guide itself was being consulted. (DCOM: The Sun Makers)

Just prior to becoming the Fifth Doctor, Peter Davison made a cameo appearance in the BBC's 1981 adaptation of the first book as the "Dish of the Day". His wife, Sandra Dickinson, played Trillian in the miniseries.

After Douglas Adams' death, Eoin Colfer was given permission by Adams' widow to write an additional novel in the series. This became And Another Thing.... Colfer later wrote PROSE: A Big Hand for the Doctor for the Puffin E-books range.

Neil Hannon, who sang the jazz songs Song for Ten and Love Don't Roam for Tenth Doctor-era Doctor Who, also sang a cover of the song So Long, And Thanks For All The Fish for the end credits of the 2005 Hitchhiker's Guide to the Galaxy theatrical film.