With the BBC giving his creation a late-night time slot indicating that they don’t really know what to do with it, Douglas Adams bursts onto the scene with the premiere of his radio series The Hitchhiker’s Guide To The Galaxy. Another attempt at mixing comedy and science fiction, Adams’ densely-worded style of wit catches on with an audience that’s never heard anything like it before. Hitchhiker’s Guide goes on to conquer nearly every medium exposed to it in the years to come. 
The second episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio 2. Mark Wing-Davey plays the role of Zaphod Beeblebrox for the first time, a character he will also go on to play in the series’ television incarnation.
The third episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio 2.
The fourth episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio. Richard Vernon and Jim Broadbent guest star.
The fifth episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio. Roy Hudd guest stars. This is the first of two episodes co-written by John Lloyd, though his contributions are frequently downplayed by Adams in later years.
The sixth episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio. This is the second episode co-written by John Lloyd, though his contributions are frequently downplayed by Adams in later years. Due to the unexpected popularity of the six-episode series, the BBC asks Adams for more Hitchhiker’s Guide, but in the interim he has also taken on a new full-time job as script editor of Doctor Who, making it harder to simultaneously write another six-episode radio series.
The seventh episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio, initiating the second series of the now-hit cult science fiction phenomenon, the rest of which won’t be broadcast until the following month. This episode serves as a kind of Hitchhiker’s holiday special as a result. (Some elements of the second radio series will go on to form the basis of Adams’ novel The Restaurant At The End Of The Universe.)
The eighth episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio, continuing the second series of the now-hit cult science fiction phenomenon. (Some elements of the second radio series will go on to form the basis of Adams’ novel The Restaurant At The End Of The Universe.) Valentine Dyall (Doctor Who’s Black Guardian) guest stars.
The ninth episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio, continuing the second series of the now-hit cult science fiction phenomenon. (Some elements of the second radio series will go on to form the basis of Adams’ novel The Restaurant At The End Of The Universe.)
The tenth episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio, continuing the second series of the now-hit cult science fiction phenomenon. At this point, the story diverges into material that will not be repeated in later iterations of Hitchhiker’s Guide; Rula Lenska and John Le Mesurier guest star.
The 11th episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio, continuing the second series of the now-hit cult science fiction phenomenon. At this point, the story has diverged into material that will not be repeated in later iterations of Hitchhiker’s Guide; Rula Lenska guest stars.
The 12th episode of Douglas Adams’ breakthrough radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio, ending the second series of the now-hit cult science fiction phenomenon. The conclusion of this episode effectively ends the series, though this ending is ignored by all later Hitchhiker’s Guide media, including the 21st century revival of the radio series, which will take its cues from Adams’ post-radio-series novels. Jonathan Pryce, Rula Lenska, and Ken Campbell guest star.
The 13th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is first broadcast on BBC Radio, beginning a radio adaptation of Douglas Adams’ novel Life, The Universe, And Everything and reuniting most of the original radio cast (though even the late Peter Jones is represented via brief clips from the 1970s radio series before being “rebooted” to the voice of actor William Franklyn). Adapted by Dirk Maggs, this is the first Hitchhiker’s Guide radio project undertaken after Adams’ death in 2001. Toby Longworth guest stars.
The 14th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, continuing Dirk Maggs’ adaptation of Douglas Adams’ novel Life, The Universe, And Everything with most of the original radio cast. Real-life BBC cricket commentators Henry Blofeld and Henry Trueman appear as themselves.
The 15th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, continuing Dirk Maggs’ adaptation of Douglas Adams’ novel Life, The Universe, And Everything with most of the original radio cast. An archival audiobook recording of the late Douglas Adams allows the Hitchhiker’s Guide creator to play the part of Agrajag.
The 16th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, continuing Dirk Maggs’ adaptation of Douglas Adams’ novel Life, The Universe, And Everything with most of the original radio cast. An archival audiobook recording of the late Douglas Adams allows the Hitchhiker’s Guide creator to play the part of Agrajag; Joanna Lumley (Sapphire & Steel, Absolutely Fabulous) also guest stars.
The 17th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, continuing Dirk Maggs’ adaptation of Douglas Adams’ novel Life, The Universe, And Everything with most of the original radio cast.
The 18th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, concluding Dirk Maggs’ adaptation of Douglas Adams’ novel Life, The Universe, And Everything with most of the original radio cast. A radio version of the fourth novel, So Long, And Thanks For All The Fish, will follow in 2005.
The 19th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, commencing Dirk Maggs’ adaptation of Douglas Adams’ novel So Long, And Thanks For All The Fish, featuring the entire surviving cast of the original 1970s radio series. Jane Horrocks (Absolutely Fabulous) guest stars.
The 20th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, continuing Dirk Maggs’ adaptation of Douglas Adams’ novel So Long, And Thanks For All The Fish. Hitchhiker’s Guide TV regulars David Dixon and Sandra Dickinson make their first appearances in the radio series.
The 21st episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, continuing Dirk Maggs’ adaptation of Douglas Adams’ novel So Long, And Thanks For All The Fish. Christian Slater (Mr. Robot, Heathers) guest stars.
The 22nd episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, concluding Dirk Maggs’ adaptation of Douglas Adams’ novel So Long, And Thanks For All The Fish. Astronomer Sir Patrick Moore appears as himself.
The 23rd episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, the beginning of Dirk Maggs’ adaptation of Douglas Adams’ final Hitchhiker’s Guide novel, Mostly Harmless. Jonathan Pryce, Rula Lenska, Mitch Benn, and Andrew Secombe guest star.
The 24th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, adapting the novel Mostly Harmless. Jonathan Pryce and Andrew Secombe guest star.
The 25th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, adapting the novel Mostly Harmless. Griff Rhys Jones and Andrew Secombe guest star.
The 26th episode of the radio science fiction comedy series The Hitchhiker’s Guide To The Galaxy is broadcast on BBC Radio, concluding Dirk Maggs’ adaptation of the novel Mostly Harmless. Maggs takes liberties with the end of Adams’ novel, negating the book’s original ending (for which Adams himself had expressed regret after publication) and reuniting most of the original cast for a happier ending than their characters met in print.