Image caption Douglas Adams' sci-fi comedy was turned into a TV series in 1981

Writing that Douglas Adams cut from his Hitchhiker's Guide to the Galaxy novels is to be published for the first time after being found in his archive.

He wrote 16 chapters for an early version of Life, The Universe and Everything - but abandoned it, filed the typescript away and started again.

It has now been found, along with other unseen passages, in an archive of his work at the University of Cambridge.

Extracts will be included in The Frood, a new biography by Jem Roberts.

Image caption Adams (third right) oversaw the original BBC radio series at the end of the 1970s

The Hitchhiker's Guide to the Galaxy, in which Arthur Dent travels the universe after Earth is destroyed, first gained popularity as a BBC radio series in 1978.

An initial novel was published in 1979 and was followed by four more. Adams died in 2001 at the age of 49.

Adams' family gave Jem Roberts permission to look at his papers after they were loaned to St John's College, Cambridge.

They included the abandoned draft for Life, The Universe and Everything, the third book in the series.

"The original version was going brilliantly - he had loads of really funny chapters and scenes - and then he just decided to abandon the whole lot and start from scratch," Roberts told BBC News.

"The book that we know has exactly the same plot. He'd written a version that was about two thirds of the way through before he abandoned it.

"A lot of people thought it had gone in the bin. But no. The manuscript with about 16 chapters is right there in St John's College."

Image caption Simon Jones and Richard Vernon appeared in the TV version

When he started the book from scratch, Adams kept the story outline but rewrote most of the action, leaving "only the odd scrap that's recognisable", Roberts said.

Asked why Adams rejected the manuscript, the biographer said: "It was during the period when he split up with his girlfriend, which was a major ruction in his life.

"He was extremely unhappy at the time. I think he just wanted a whole fresh start."

Roberts' book, which will be published in September, will also include passages that were left out of the original Hitchhiker's Guide to the Galaxy novel.

"There are two short extracts, which are very entertaining actually, which were cut from the first book," Roberts said. "They're little asides, maybe a couple of pages each.

"One of them is all about the history of the Dentrassi, who work on the Vogon ships, and there's a bit where Arthur goes on this long reverie about science, which is very out of character for him, which I think is maybe why it got cut."