The definitive version, and where it all started. The original six episodes were first broadcast on the 8th March 1978. You'll find versions of this available on cassette and CD from Amazon and the BBC Shop . Here's what's available:

• Series 1 (6 episodes) on CD
• Series 1 (6 episodes) on Cassette
• Series 1 and 2 (12 episodes) on CD
• Series 1 and 2 (12 episodes) on Cassette
• Available for download from Audible.co.uk
• The original radio scripts Book

• Series 2 (6 episodes) on CD
• Series 2 (6 episodes) on Cassette
• Series 1 and 2 (12 episodes) on CD
• Series 1 and 2 (12 episodes) on Cassette
• Available for download from Audible.co.uk
• The original radio scripts Book

Twenty-four years after the original series, there's more. Series 3 (the Tertiary Phase) reunites many of the original series cast, and is based on Douglas' third book, "The Restaurant at the end of the Universe" - Based on the Krikket wars.

Sadly, Peter Jones (the Guide) and Richard Vernon (Slartifartfast) are no longer with us, so their parts are played by William Franklyn and Richard Griffiths.
The series is an 'Above the Title' production - produced by Bruce Hyman & Helen Chattwell for BBC Radio 4 - It was adapted, directed and co-produced by Dirk Maggs. For more, see Radio 4's Hitch-hikers page.

The Tertiary phase was broadcast in Sept/Oct 2004 and is now available on CD and audio cassette from Amazon or the BBC Online Shop - the CD contains the unedited versions, with an extra 20 minutes of material.

Some notes:

• Being based on book 3 presented the team with a challenge - Book 3 starts with Ford and Arthur stranded on prehistoric earth, but that problem was solved back at the start of the second radio series. The second radio series sees Arthur leaving the Ruler of the Universe's shack, stranding Ford and Zaphod... A tough one, and possibly a cop-out?
• The people of Krikket, are played by Michael Fenton Stevens and Philip Pope (both from the BBC radio comedy show, Radio Active). Geoffrey Perkins, producer of Series 1 and 2 was also a member of the Radio Active team.
• The character of Agrajag is played by the late Douglas Adams, who reportedly always wanted to play the part. His narration from an earlier talking book was used.
• Series producer Bruce Hymen plays the part of the dying Arthur Philip Deodat

• Series 3 on CD
• Available for download from Audible.co.uk
• The radio scripts Book 2 - Now available

Based on Book 4... "So Long and Thanks for all the Fish" - Arthur's home, and in love with Fenchurch, a girl famous for her lunchtime experience in a cafe in Rickmansworth.
Started transmission at 6:30pm May 3rd 2005 on BBC Radio 4. More on the BBC site.

Some notes on this series:

• Episode 1: Arthur's left Krikket, and an update to the guide sets him on his way to a familiar planet.
  Noticed that the music in the Handold bar is the same as the track playing at the flying party. Chris Emmett plays the Bar Bird
• Episode 2: In which Arthur returns home, Ford's in transit, and June Whitfield sells Arthur a ticket with mixed fortunes.
  This episode features the voice of Geoffrey Perkins as Arthur's old boss (a BBC radio producer) - Geoffrey Perkins was the original BBC radio producer for the series in the late 70's. Also, Rob McKenna is played by Bill Paterson, who played the Assistant Arcturan Pilot in Episode 7 back in 1981. Also noted that the dead kitten reference has been edited from the radio series
• Episode 3: Arthur and Fenny in love, and flying bodies over Islington...
  Features Stephen Fry as Murray the reporter (Stephen is the Film's Guide voice). Also features Christian Slater as Wonko the Sane. I was sad to hear that Arthur's biscuit story was missing - an especially memorable bit from the book - but now having got the CD, find that this episode has an extra 10 minutes, including the biscuit story and the bit about the fire-breathing dragons. Is the track played at the end, the Dire Straits track to which Douglas refers?
• Episode 4: The last in this short series sees a UFO land on Harrods and a trek to see God's final message.
  Favourite moments - the Share and Enjoy ringtone (wonder how long before someone's made that available for download. Above the Title Productions... any chance of a copy?). I see someone's snapped up Rob McKenna's .com address - 50 hits as of the day of transmission, and 1250 24 hours later! Also, the earthbound Tricia McMillian is played by the TV series Trillian - Sandra Dickinson

Here's where to get this series:

• Series 4, the Quandary Phase, is available on double CD and Cassette. Both feature extended versions of the transmitted episodes, but you're best off going for the CD version, which runs at 2 hours 25 minutes, adding an extra 30 minutes! Also, the Hitchhiker's theme has undergone a rather smooth remix for the CD release (arranged by Philip Pope, featuring The Illegal Eagles tribute band)- nicely done boys!
  You can order these online direct from the BBC Shop or from Play.com.
  
  
• Available for download from Audible.co.uk
• The radio scripts Book 2 - Now available

Based on the last Hitchhiker's book, "Mostly Harmless" - Sees Arthur meeting an unexpected relative, occupants of the planet Rupert, and catches up with Trillian's TV career. Ford makes a visit to the Guide's offices and meets the Guide Mark II. Abridged into just four episodes.

First episode transmitted on 31st May 2005 on BBC Radio 4.

Some notes:

• Episode 1: Arthur's left Krikket, and an update to the guide sets him on his way to a familiar planet.
  Harsh - my favourite part of the book is missing - "Click... hum". Mostly Harmless is a longish book, and some heavy trimming has gone on, that having been said, there's some new content here too - Zarniwhoop as the Guide Editor? Good to see a few extras such as the body debit transporter SFX, Rula Lenska as The Bird Guide (she was Lentila in Series 2), and Michael Fenton Stevens (former Person of Krikket), now as a nameless Grebulon.
• Episode 2: Arthur meets a polesitting soothsayer, Zaphod's been hiding in a computer, one of the Trilans is abducted, and Zarniwhoop's secret is revealed.
• Episode 3: Griff Rhys-Jones... great choice as Old Thrashbarg. Nice little nod to Accurist with Brian Cobby as the voice of the Speaking Clock. Some heavy editing from the book, but as the action on Lamuella is pretty slow, this is no bad thing. Shame the stuff about the Telephone Riots didn't make it into the series or the exended CD material though.
• Episode 4: OK - my feelings are still mixed on this one. The is the last episode, and the book's ending is pretty damn final... this last radio episode is pretty close to the ending of the book, and ties up a whole lot of loose ends... but the ending wasn't quite what I was expecting... my first reaction was annoyance that the ending wasn't true to the book, however, it was just so well done, that I'm happy to let them off - since hearing the episode again (the extended CD version), actually, I'm now happy - a good end to the series, and I'd recommend that anyone gets the CD version to hear an extended end, and 10 minutes of extended material (plus a great version of the Journey of the Sourcerer theme). Other highlights - the post-destruction guide reprise, "closing brackets and endifs",Trillian meeting Trillian and The King's song (incidentally, this isn't the first time that Philip Pope's been the voice of the King - he's done it before in an early Radio Active). If you're reading guys - clever use of an old effect to create a new planet for Jeltz to destroy - "I have eyes!"
  Well done to all concerned - a great end to an excellent remake. Off now to read the book of the scripts, to find out a little more about the new series. So long, and thanks...

Here's where to get the final series:

• Series 5 on CD -Now available
• Available for download from Audible.co.uk
• The radio scripts Book 2 - Now available