By Tim Masters
Entertainment correspondent, BBC News
Eoin Colfer is the author of the best-selling Artemis Fowl series
When Eoin Colfer sat down to write the sixth instalment of the Hitchhiker's Guide To The Galaxy, he sought inspiration in the music of the late 70s.
"I sat in a room on my own, I downloaded Kate Bush, Bowie and Queen and made up this Hitchhiker playlist. I just put it on and it took me back to that era."
The Irish author holds up his hand and references a joke from the first novel: "And I got my digital watch, of course!"
If Colfer - best known for his Artemis Fowl children's books - is nervous about taking on the 30-year-old cult series by the late Douglas Adams, he isn't showing it.
His novel And Another Thing... will be published on Monday. Mostly Harmless, the last Hitchhiker book by Adams, was published in 1992. The author died of a heart attack in 2001, aged 49.
"It's like Monty Python meets Mel Brooks - in space," says Colfer, describing Adams's style. "That's what I try to do, though my book is probably more on the Mel Brooks side."
Fans of the Hitchhiker's Guide series - also known as H2G2 - will rejoice that most familiar elements are intact: There are witty Guide entries, the Vogons and their awful poetry, the Infinite Improbability Drive and, of course, Arthur Dent and his companions Ford Prefect and Zaphod Beeblebrox.
And Another Thing... comes out on the 30th anniversary of the publication of Adams' original novel in 1979. The new book was written with the approval of Adams's widow, Jane Belson.
The book launch is at the HitchCon 09 event in London on Sunday
Colfer is enthusiastic about one of his new characters - the Irish-accented Hillman Hunter. "It's another riff on Douglas - a reference to an old car, like Ford Prefect," he says.
In the surreal Hitchhiker universe, it's no surprise that we first meet Hillman Hunter as he interviews candidates for the position of god on a small planet.
Colfer has woven several Irish elements into the book. There's even a subtle twist on a WB Yeats poem on page 6.
"That was really for my mum because she's a Yeats scholar," laughs Colfer. "I'm showing my mother that I'm not a total idiot. I also did a little reference to my Artemis Fowl guy on the first page."
So why is H2G2 still so strongly held in affections of a generation?
"It had all the elements that makes it popular with teenagers," says Colfer.
"When you read Hitchhiker you realise it's very anti-establishment. The whole Vogon thing is a huge slag-off to the bureaucrats. It pokes fun at religions and it's very pro-anarchy."
He adds: "It's very catchphrase-y too. For me and a group of friends in Wexford, it became our Monty Python. We had all of these little one liners and we would contrive to get the number 42 into as many conversations as possible."
[The number 42 is - in the Douglas Adams universe - the answer to the ultimate question of life, the universe and everything.]
The original book also spawned a BBC TV series starring Simon Jones
Colfer's book joins a list of recent "authorized sequels" of classics like Peter Pan, James Bond, Dracula, and Winnie-The-Pooh.
The author says he "tried to shut out the whole business side of it" when he was writing.
"I knew there would be a lot interest, but I didn't really know how much. I feel like someone in the first Big Brother show. They came out to this total hysteria - they had no idea. I feel a little bit like that now."
With this, his first novel aimed at adults, Colfer admits he felt a lot of freedom when it came to swearing and sex references.
"I thought I was going to go wild," he laughs. "But I'm a moral parent, so I thought inter-species sex might not be a good idea - my son might read this. But I did put in a few naughty words."
Any proper Hitchhiker's Guide interview should end with some random, improbable questions:
What would Hitchhiker's Guide say about Eoin Colfer?
In one of my very first interviews in 2001 I was asked to describe myself in three words: I said I was "short, grey and nervous". That's probably what the guide would say: "Short grey and nervous - and mostly harmless. Did not please all Hitchhiker fans of Earth, but did his best."
What's the most improbable thing that's ever happened to you?
My wife gave me a voucher for a parachute jump, and I thought later, 'why, just as you've made it big, would your wife give you a voucher for a parachute jump?'
But I think the most improbable thing is getting this phone call to write the Hitchhiker's Guide.
I remember seeing a documentary about Gary Numan, who I also kind of like. His wife, when she was young, loved Gary Numan and she wrote in her diary "I'm going to marry Gary Numan". And she grew up and she did marry Gary Numan.
I feel a bit like that. Not that I'm going to marry Gary Numan. But I feel like I've always wanted to do this, and it's actually happened.