Adams initially "came up with various ideas and various permutations of people living in bedsits and this sort of thing" as this "seemed to be what most situation comedies tended to be about.

"[4] Adams said in an interview that when Brett proposed a radio science fiction comedy series, he "fell off his chair...because it was what I'd been fighting for all these years".

[11] As Brett had since left the BBC and Adams had been commissioned to write a four-part Doctor Who serial ("The Pirate Planet"), the final five episodes in the first series were produced by Geoffrey Perkins.

[15] Adams wrote the main parts of Arthur Dent and Ford Prefect with actors Simon Jones and Geoffrey McGivern in mind.

[16] The radio series (and the LP and TV versions) featured narration by comedy actor Peter Jones as "The Book".

[17] Following another actor dropping out of the production, Bill Wallis was called in at short notice to play two parts, Mr. Prosser and Vogon Jeltz.

[17] One character appearing in the pilot who was dropped from subsequent incarnations of the story was Lady Cynthia, an aristocrat who helps demolish Dent's house, played by another ex-Cambridge Footlights actress, Jo Kendall.

On board is Ford's semi-cousin and President of the Galaxy, Zaphod Beeblebrox; a woman Arthur met at a party, Trisha "Trillian" McMillan; and a depressed robot, Marvin.

Beeblebrox is searching for the mythical planet of Magrathea, where Arthur meets Slartibartfast and learns the answer to the "Ultimate Question of Life, the Universe and Everything", which it turns out is "42".

Arthur and the others find themselves at the Restaurant at the End of the Universe, then held captive aboard a Golgafrincham ship about to crash-land on prehistoric Earth.

After surviving the Total Perspective Vortex on Frogstar World B, Zaphod returns to The Heart of Gold and rescues Arthur and Ford from prehistoric Earth.

When the Heart of Gold is attacked by Vogons pursuing the surviving Earthlings, the ghost of Zaphod’s great-great-grandfather transports the ship to Brontitall, a planet populated by a race of bird people.

Separated by falling off a giant statue depicting Arthur, they hear about the rudest word in the universe and the Shoe Event Horizon.

Escaping using a 900-year-old spaceship, the three find themselves in the offices of the Guide editor, Zarniwoop, and we discover that it was Zaphod who accidentally signed off the Earth for destruction.

[22] Producer Geoffrey Perkins recalled that the technology available in 1978 for mixing sound effects at the BBC's Paris Theatre radio studio was limited.

Other BBC staff members who worked on the first two radio series included Alick Hale-Munro (chief sound engineer) and Anne Ling (production secretary) and the "Technical Team" is given as: Paul Hawdon, Lisa Braun (studio manager), Colin Duff (studio manager), Eric Young, Martha Knight, Max Alcock and John Whitehall.

Further scheduled recordings on 11 July and 1 August of that year were also cancelled, this time due in part to Adams trying to work on the LP re-recordings of the first series, as well as its novelisation.

[citation needed] The theme tune used for the radio series (and all subsequent adaptations) is "Journey of the Sorcerer", an instrumental piece composed by Bernie Leadon and recorded by the Eagles on their album One of These Nights.

The Hitchhiker's Guide to the Galaxy: The Original Radio Scripts lists works including A Modern Mass for the Dead (Requiem) by György Ligeti, A Rainbow in Curved Air by Terry Riley, Volumina by György Ligeti,[27]: 33  "Wind on Water" by Robert Fripp and Brian Eno, Poppy Nogood and the Phantom Band by Terry Riley, Cachaca by Patrick Moraz,[27]: 51  "Shine On You Crazy Diamond" (intro) by Pink Floyd,[27]: 62  "Rock and Roll Music" by The Beatles, Also sprach Zarathustra (intro) by Richard Strauss,[27]: 63  Katakomben by Gruppe Between, Space Theme by Stomu Yamashta, Oxygène by Jean Michel Jarre, "That's Entertainment!"

by Howard Dietz and Arthur Schwartz, "Over Fire Island" by Eno,[27]: 71  Miracles of the Gods by Absolute Elsewhere, Mikrophoniet by Karlheinz Stockhausen,[27]: 88  Melodien by György Ligeti, The Engulfed Cathedral by Isao Tomita,[27]: 107  Volkstanz by Gruppe Between,[27]: 128  and "What a Wonderful World" by Louis Armstrong.

Simon Jones recalled that Adams was initially disappointed at the scheduling as the timeslot was allegedly guaranteed to turn a programme into a "cult" (i.e. a small but dedicated listenership).

[34] The first series was noted for its unusual concept, out-of-context parodies, "semantic and philosophical jokes",[1] compressed prose and "groundbreaking deployment of sound effects and voice techniques".

[38] The storyline set out by the initial radio series has since appeared in numerous formats including a 1984 computer game and a 2005 feature film.

The project was restarted in September 2001 by Maggs, Helen Chattwell and Bruce Hyman, with help from Jane Belson and Ed Victor.

The parts of The Book, Eddie the Computer and Slartibartfast were recast to replace actors who had died, with William Franklyn, Roger Gregg and Richard Griffiths taking over these three roles, respectively.

In the final part, Dent and Trillian meet the computer behind the Supernova Bomb and there is another attempt to find the Ultimate Question to Life, the Universe and Everything.

[55] The names for these series were chosen because they sound "less daunting, more memorable and are a bit easier to spell" than the standard terms quaternary and quinary.

This includes using the new Philip Pope signature tune, so the material can be released worldwide, which has required John Marsh to re-record his announcements so they could be mixed in.

A scene from Fit the Third was cut from commercially released recordings of the radio series because it featured copyrighted music that could not be cleared.

[29] For the CD and cassette releases of the Tertiary Phase in the United States, and all CD and cassette releases of the Quandary and Quintessential Phases, the instrumental title theme, "Journey of the Sorcerer", composed by Bernie Leadon and originally recorded by US rock band the Eagles, was re-interpreted by The Illegal Eagles, a tribute band, using an arrangement by Philip Pope.